Buick - Regal :: Rough Idles And Misfires On Cold Starts
Sep 13, 2014
1991 Regal, 3800 v6.
So here's an interesting observation. When i turn the ignition to ON, I hear no sound nor feel any vibration from the fuel pump. Is there any scenario where a fuel pump fails to prime yet kicks into gear after a start? So, I've got rough idles and misfires on cold starts. Before I start replacing parts my diagnostic plans is as follows:
Remove and inspect spark plugs.
Inspect and test starter coil/distributor (still have to research how to do this)
Test resistance on fuel injectors.
Test pressure drop on fuel rails.
Test compression for possible small head leak.
I'm wondering, if I do have a tiny head leak that is letting in a drip or two of coolant after hours of the engine sitting, will I be able to see this on the gauge doing a compression test? I've never done one before and still need to buy a gauge, but maybe I'm better off just doing the other tests and if they all check out I can be certain it is a minor head leak.
My assumption is that I have a leaking injector; just trying to do things the proper way.
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My son is about to purchase his first car. A 98 Buick Park Regal. Feels like it idles rough, and has a little hang-up when it shifts. Seller claims it's due to needing a transmission mount replaced. Does this sound viable?
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1991 Buick Regal, 3800 V6
Having a rough idle on a cold start. After some research and closer inspection of the vehicle, I'm quite certain I have at least one leaking injector that is flooding a cylinder and causing the car to misfire on a cold start. I'm also not at the gas mileage I should be at.
So I'm wondering, is fuel injector replacement as straightforward of a job as it looks? Any major issues I could run into in doing a replacement?
I'm planning on replacing all six injectors (I can get them for $50 each buying online with a discount code), but given that the vehicle is so old am I better off just replacing the faulty ones? I'm assuming pulling the spark plugs and seeing which cylinder is wet will tell me which I need to replace.
And one more question: Is there a way to depressurize the fuel system when I park the car for the night, thus preventing fuel (or most of it) from leaking into the engine until I get this fixed? I've read that just unscrewing the gas cap can depressurize the system.
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The problem I have is when it is cold out under 40 degrees, my car starts rough and idles rough until it gets to temperature. My research has concluded it may be cold start. Does this sound right?
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1993 Buick Regal 3.1l V6 Multiport injection
Problem: The care currently has a hard start, and a fluctuating idle. I bought the car a year and a half ago it still has low miles about 94,000. The care used to start fine but had a fluctuating idle in the range of 750 to 2500 rpm. My brother who is a mechanic and doesn’t live near, do all the gaskets when he visited. Then the idle fluctuation dropped to 750 to 1000rpm, when the car rpms fluctuate there is a whirring sound I can hear from the cab, like a pump or pull system. On occasion there is a vibration as well but it is inconstant and irregular. Fuel pressure seems to fluctuate as well. If the car will not start I give it a little gas and it will run fine after a minute or two, but then the idle starts to fluctuate.
No fuse issues I can tell and relays seem to be fine.Checked for lose wiring connections found, none. I have replaced:
- Hoses and gaskets
- Starter motor
- Battery
- Fuel Pressure regulator
- Fuel Filter
- Spark plugs and wires
- TPS
- Idle Air control Valve
- Crank shaft sensor
- PCV.
Right now I’m thinking it could be the fuel pump (a nightmare to change on this car), a fuel injector failing, and the ignition switch.
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I have a 2002 Nissan Quest. It starts fine, idles great. But, when I try to accelerate, the car bogs, hesitates, misfires and I get p0300 random misfire, p0325 knock sensor. I get no dtc when it is just idling. The fuel pressure is fine, regulator works good, the cam sensor is clean, the coil tests good, the compression is good, as are the wires, cap and rotor.
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I have a 1995 Buick Regal, with a 3.8L engine. When I start the car sometimes it rough idles and I have to give it a lot of gas and then it runs fine. This is completely random. Sometimes it runs just a little rough, other times really rough. The rough idling when starting the car happens about 1 out of 25 times. Sometimes when this happens I get a check engine light, most of the time not. When I am driving around I also will randomly get a check engine light, but I can't tell anything common to it. It has come on while braking, while coasting with foot off the gas and brake, normal city driving, highway driving. Also my CEL always turns off when I turn off the car and doesn't come back when I restart the car. Always.
I haven't been able to figure out what is wrong and since my car is transition OBD1 to OBD2 I can't use a OBD2 code scanner (it is an OBD1 port), nor will shorting the pins in my OBD1 type port give me codes. Being this the case I took it to a local mechanic and they scanned the computer and said they got 16 error codes. They reset the codes but couldn't get the CEL to come back on. I took it drove it for a couple of days the light came back on so I took it back to the shop and they got 18 codes out of it, but they were mostly different, with some of them giving the opposite readings of before (O2 sensor high one time, then low the next check). They said they didn't know what was going on but wanted 3-4 hours to diagnose the PCM (Powertrain control module) and would probably replace the PCM (~500 on top of the diagnostic fee). That was a bit much for me, so I took the car back.
The things I have checked are fuel pressure (seems fine at idle and revving the car in park)Vacuum is 19 and when I rev quick it drops to zero or so then up to 25 and slowly goes back to 19 (I think that means vacuum is ok). I put the gauge in the O2 sensor before the CAT and I didn't read any pressure, so I think the CAT is ok.I put on a new fuel pressure regulator, and a new fuel filter. I got the same PCM at a Pick-n-pull place and put it is my car 3 days ago. Yesterday I got a check engine light while driving again. The mechanic will charge me to check the codes, but I think it is just doing the same thing as always. I am sort of at a loss as what to do. I though it I was to dive around with a scanner hooked up and the light went on then I could see what the sensors were doing when all the trouble codes fire. I was looking at the Actron CP9190, but it doesn't log the data stream for OBD1 cars, only for OBD2.
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1991 Buick Regal, 3800 V6
As the title says, when I start the engine cold I get a slight puttering and drop in RPMs followed by the engine revving itself to about 1100 for a few seconds and then normalizing at 600. It has only actually stalled out a few times. This does not happen once the engine is near operating temperature.
Now, I did not notice this issue prior to doing some maintenance on the vehicle (radiator replacement and transmission service) and I've read that this can be caused by a faulty coolant sensor. Possible?
Battery is new.
Also, when I say cold start I mean summer temps here in Michigan. So it's happening anywhere from 50 to 90 degrees F.
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2001 Buick Regal , 125000 miles ..
A couple weeks ago I notice that my car has started making some noise and has become a rough drive. Whenever I rev, especially between 0-30 mph, its like a mini jackhammer, or a sputtering/rumbling sound when I drive.
What it could be, and what I should do?
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I own a 1996 Buick Regal with 132k miles on it, 3.1L six cylinder. The other day I was doing some general maintenance and noticed that the exhaust smelled like sulfur (rotten eggs). Now, I am loosely familiar with the causes of such a thing but not well enough to diagnose it properly the first time. The car has been idling rough since I got it (almost a year ago now), I have a feeling that it could be the O2 sensor causing the rough idle and the sulfur smell but I am not completely sure. I should have one of those fancy three-part injector cleaners done?
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I have a 98 Buick Regal. When my air conditioning works, it is beautiful. On a hot and sunny day when I pull out of the garage, I can run the air conditioning until the car is turned off. After reaching a destination and parking in the hot sun the compressor will not blow cold air. If the day is overcast or cool, the air conditioning works fine. What the problem might be?
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I have a 95 Buick Regal, V6 3.8 Liter. The symptoms are the following: stuttering idle. And lack of response at times when I try to accelerate. Like sometimes I'll be driving on the highway, and having no problems. Then I'll be going up a hill at around 55 mph, and then the car will shudder as I try to maintain a speed of 55 mph. So I have to ease off the accelerator and slow down. At first I thought this was a transmission problem, but I am guessing it's the same problem that causes my choppy idle.
So I had this acceleration problem on the highway when I was going up a hill. And a weak idle. These problems have been going on for several months now. They were annoying, but didn't seem that serious. Then all of a sudden, on a rainy day, the car was really responding poorly to acceleration at all speeds. I was able to drive around, but I couldn't count on the car responding right away when I hit the gas pedal. And the car would shudder at times. Then, I didn't drive the car for a few days, and then it was dry, no rain, and the car ran better. So I am thinking humidity makes the problem worse.
I have also noticed over the past few months, that the car runs best when I start it up after a few days of not running it. Then if I drive the car a few miles and let it sit for about 2 hours or so, it would idle weakly when I would start it up again. The car's been doing that for several months now, but it wasn't really affecting the drivability or the response of the car when I hit the gas pedal.
Now it's gotten much worse. So, I've already replaced the following items myself to no avail: mass air flow sensor, oxygen sensor, and egr valve. I am guessing the next thing to fix is the pcv valve. But I also think it might be the fuel pump. My first guess though is the pcv valve. What else could it be? And is there any easy way to test to see if the fuel pump is going bad? Or should I just take out the pcv valve and see if it looks bad?
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I have a 1995 Buick Century with 149,000 miles that will occasional and randomly idle rough when started warm. Also, on several occasions it will idle so rough it kills the engine and I'm unable to start the engine until the thermostat reads completely cold. I've taken it to 2 separate mechanics who both are unable to pull any error codes (even after the engine has died) and are unable to duplicate the problem. When it does idle rough most of the time I can rev the engine, put it in gear and drive it for a few minutes and the problem disappears. Other times I try to put it into gear and it kills, I put it into park and try to restart the engine and the engine will start for a brief second and then die and will die faster each time I restart until the engine doesn't turn over at all. Then once the thermostat reaches 'C' it starts up like there was no problem at all.
Here is a list of recent pertinent repairs:
- Replaced Battery 12/2/11
- Replaced plugs and wires 4/11/12
- Throttle Body Gasket and Fuel Filter Replaced 3/18/13
- PCV Hose replaced 2/19/14 (last mechanic's guess on the problem)
I don't notice any signs of a rich fuel mixture or abnormal exhaust (there was a discussion with a Buick with no start that had this).
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I have a 2003 2.0 gas Jetta (181k miles, automatic.) that won't rev over 3k, starts rough, idles rough and wont stop setting a P0341 cam position sensor code.
The car was not running when i got it, i replaced the coil pack and it ran but not over 3k. Cleared codes, it sets the P0341 immediately.
Had timing belt, water pump, tensioner and cam pos sensor replaced. Still, sets p0341 code, starts rough, idles rough and wont rev over 3k.
The throttle servo makes a little noise when actuated, shop thinks this is my demon - suggests replace throttle body.
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Just recently my Prius Taxi with 340,000+Km has developed a little problem,it starts fine but after 20-30 seconds it begins to feel like it's not running properly on all four cylinders,if i go to the exhaust pipe it seems like it's spluttering slightly.
Yesterday I changed the plugs,checked air filter and all connections,everything fine, when I accelerate it feels hesitant but after the car gets up to temp it seems to go away,it only happens when i start it first thing or if it's been left for a few hours, it's never had the throttle body cleaned and I'm wondering if what I'm describing is a symptom of this?
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My 94 850 turbo wagon starts rough and idles very high. the rpms dont come down. After turning car off, wont restart again unless I let in sit for a while.
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We have a Ford Focus wagon that idles rough once the engine starts coming up to temperature. When you first start the car it's fine. For example, today I started the car, drove it up the road to the store and it was fine, but upon returning to my driveway just a few minutes later, as the engine temperature was just starting to come up, it started idling really rough. The idle is so rough it sounds like it's on the verge of stalling, but it never has actually stalled. An oxygen sensor has been replaced and it was good for a while, but now the problem is back. The check engine light is on as well.
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I just got a 4.6 4WD Explorer in for rough running. It had timing chain noise and some odd codes for primary coil H codes along with cylinder 8 misfire.
I replaced the coil to get rid of the "H" code and it was fine. Still misfires on 8, and I really don't care because it's coincidence that the timing could be affecting it or perhaps.... bent valves!
The vehicle starts and idles a bit rough. Can't go very fast, and of course I know I should run it as little as possible!
Here is the deal, how should I present this to the customer? Should I let him know that some valves could be bent after replacing the chain (and all associated parts) and that it could still be effed? Or will I be fine after replacing? Pretty much, where they had a tensioner failure/guide breakage and valves bent too?
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We're talking about a 2002 Subaru Forester with only 80,000 miles on it.
This winter, the cold seems to have taken its toll. The fuel economy is bouncing around between 16 and 24 MPG and the car runs a bit roughly. Especially when it's colder (<30 F) there is often a lack of power/RPM when depressing the gas pedal. The problem is worst in city driving, but exists on the highway also. It doesn't go away during my 15-20 minute commute. For a period of a couple weeks, it was even easy to induce misfires (I think that's what they were; quiet pffft pffft pffft sounds during severe lack of power) by fully depressing the gas. But even if you half-depress and hold the pedal steady, the car will accelerate weakly and then sometimes surge forward. Other times it seems to be idling strong and running rich. Now that it's warmer (>40 F) the problem has lessened, but I've also started feeding it 93 octane gas and the car feels rougher than normal.
A year or two ago, I replaced the front oxygen sensor and spark plugs (prior to problem). This winter, I took it to a mechanic who couldn't explain the problem and replaced the spark plug wires.
Based on my reading, it seems like the only other most likely culprit is the manifold air pressure (MAP) sensor that's mounted on the intake manifold. I haven't worked up the effort (and can't find my multimeter) to do an electrical test of the MAP sensor's output itself. I'm also not keen on just buying a $270 part without sound evidence, nor paying for ill-informed guessing by lesser mechanics (than yourselves, of course!). I also have a sneaking suspicion that the automatic transmission could be slipping -- when I drive with 2 adults and two kids in the car up a hill, it seems more underpowered than days of old.
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I've got a 2009 Tiguan with 65k miles on it. A few weeks ago I noticed some issues with running rough during a cold start. I only noticed because the engine would vibrate considerably more than usually for the first few minutes of operation, and would idle at around 1050-1100rpm instead of the usual 750rpm. After warm up, things were fine. Suddenly the issue got bad real fast - wife was out and the MIL light came on, EPC light came on, and the car was running extremely rough. We managed to drive it home (2 miles) doing under 20 the whole time on side streets. Once I hooked it up to my OBD reader, I was seeing cylinder misfire codes on all four cylinders.. P0300, P0301..P0304, all five codes simultaneously.
Since the car was due for an oil change and hit 65k miles recently, I decided to throw new plugs in there to see if that would work. It did, at first.. A day or two it ran completely fine, no rough starts, no misfires, I thought I had solved the problem. The old plugs had some deposits on them and were original, so I thought I was in the clear. Two days later, same thing happened again.. EPC light, barely running and misfires on all four cylinders..
I read up some online and decided to order new ignition coils. Took a few days, but I got four new coils and threw them in. Again, problem solved it seemed. No more EPC light, misfire codes didn't come back and no more rough starts. I drove a good 40 miles with no problems at various speeds, but started noticing some misfires during acceleration (slightly rough acceleration, almost feels like a back and forth rocking motion, very slight). Sure enough, after a cold start I'm seeing the engine run a bit rough again with misfires. This time, only P0304 (misfire on cylinder 4) is thrown, and it only shows up as a "pending code" (engine light flashes for a few moments during start, but does not stay on).
I checked my connections, swapped the plugs and coils in what I thought were cylinders 3 and 4 (closer to the driver side), nothing. I swapped what I think are cylinder 1 and 2 (passenger side) just to be sure, but still nothing. At this point I'm pretty lost. I know enough to be dangerous with a carbureted engine, but am lacking in knowledge when it comes to a fuel injected turbo charged VW engine. It seems to be cylinder 4 misfiring consistently at this point according to the OBD reader.
Also of note.. I had some misfire problems last year, and had my intake manifold replaced as part of a recall (also had carbon deposits removed at the same time). Can a carbon build up occur this fast? Can it be the injectors?
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I just replaced the water pump and put it all back together, now it won't run well enough to drive. Checked vacuum system, all sensor connections, hoses, gas cap, changed fuel filter, I can hear the fuel pump kick in, reset system with battery disconnected and have looked at everything I can think of so far.
Now - starts fine, idles about 10 seconds and then begins to idle rough and dies. If I use the throttle I can often keep the idle up, but then backfires or acts like no fuel and again dies. Used fuel cleaner and made sure there was plenty fuel in tank.
I am looking at replacing sensors at this point but which one first?? They get a bit expensive real quick.
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