Lexus SC430 :: Intermittent Rough Idle
Feb 20, 2011
I have done hours of searching about the rough idle on the SC430. What I haven't been able to find is any information about an intermittent rough idle. I have cleaned my MAF sensor twice.
I am having my mechanic replace the radiator tomorrow because of a leak and he is also replacing the idler pulley and the belt tensioner (one of them is making a noise and I purchased an extended warranty!) At the same time he will be doing a throttle body cleaning. I had my timing belt replaced as well as the water pump and had my mechanic check all the spark plugs and all were fine.
I am going to have him check the motor mounts as well. The RPM's are fine with the AC on or off and I have used Lucas fuel treatment on this current tank of gas without any results and my next tank I will try Seafoam as suggested by my mechanic.
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Idle is good in gear without load but if i turn on the AC or the headlamps the idle speed increases slightly but is not as smooth ...very weird...
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About every 10 to 20 minutes while driving I hear 5 or six intermittent beeps. No warning lights or anything, just the beeps. What is it? I have a 2002 SC430.
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One channel (FM 90.3) delivers perfect sound for two seconds, then complete silence for a half sec. then two more seconds of perfect reception. No fade, no static, just on and off regular as a clock. This station broadcasts on two other frequencies which are behaving and 90.3 comes in fine on my other vehicle.
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2002 ... I've been getting a soft engine fault all three lights on and reduced power. This usually occurs if I accelerate hard but also happens if I take a small pot hole in the front, a little bump seems to trigger it as well. Also engine resets to normal after removing key.
It's not logging the fault as had dealer read ECU and said was not logged.
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When I take off from a start it will intermittently stumble or hesitate, seems to be around 1500 rpm. have also noted it at higher speed while cruising. its more like a momentary power cut than a miss fire.
So far I have done the following
new fuel filters
clean MAF
new PCV valve
new spark plugs
check all hoses and plugs etc
injector clean
checked techstream for codes. there is one for a heated O2 sensor but dont think thats it.
2002. SC430
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Lexus has diagnosed a ground fault with an intermittent connection.... I am not sure how to proceed ... Could it be a light bulb connection... or does it even have these? Can the part be serviced in place... or must I replace the whole assembly?
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This is what my car is doing after it warms up. It will do it then stop, then do it again and so on. I am pretty sure when the motor is under load it runs a little rough but is hard to tell. The car has 178,000 miles on it. timing belt was done at 113,000. I just replace the plugs and wires changed the oil and the air filter 1,000 miles ago. and it will still do it. I am at a loss as to why it keeps doing this. I have tried injector cleaner, sea foam and engine restore. What would cause this? The check engine light is not on. i replaced the crankshaft positioning sensor about 40,000 miles ago.
Its a 2003 hatch with the 1.6 5 speed .....
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My IPR value on torque pro koeo is at 14.7. Is that normal? Usually idles around 23.7-24 but when I experience a slight rough idle IPR will be 26-27. When I was under the truck last week I did see there's been oil leaking somewhere seems leaving evidence on the drivers side rear of bellhousing. Any relation?
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I just purchased my first F150, 4.6L V8, 55,600 Miles. It intermittently has a rough idle and only seems to be when the engine is hot. I've had engine and tranny mechanics look it. The spark plugs have been inspected and are within an acceptable range. The throttle body has been cleaned. There are no trouble codes of any kind. What I can check next?
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In your experience, what issues have you seen that caused intermittent rough running at idle, but did not throw a code. I have monitored (with numerous scanners/gauges) this 6.0, but cannot get a code or see any of the sensors out of spec.
At Hot idle:
IPR: 24.2
ICP: 640
ICV: 0.90
MAP: 14.7
MAF Volts: 1.5
EOT/ECT Deltas within 10 and Avg ECT=192, EOT=199
EGR Valve cleaned and EGR demanded = EGR Measured
Vehicle will run rough after long runs or towing. Cylinder Balance test showed all injectors on. What could be the cause?
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I have a 05 fx4 5.4L with 85k on it. It has started idling rough when i come to a stop light or slow down to 10 mph or less. It only does it once in a while. There doesn't seem to be any real pattern. The motor shakes until you rev it up and then it goes away.
I have cleaned the maf, put in new air filter and fuel filter. And put in a new battery. Would a coil act like that? Maybe plugs? Or a vacuum leak?
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2003 Ford Explorer 4.6 liter AWD. Having some kind of VERY STUBBORN idle / emission problem. When it started it was an intermittent rough idle, mostly going too low or making a periodic "drumming" sound that could be felt and heard at the air cleaner box. CHeck engine codes were PO 442 evap system leak. I first cleaned and inspected throttle body, mass air flow sensor and idle air control valve. I inspected hoses for leaks, including spraying cleaner to see if I could detect idle changes / leaks. I then replaced Idle Air Control Valve. Did not seem to cure problem . SO took it into Ford Dealership and they smoke tested and said needed Vapor Management Valve and Vent Solenoid. I replaced VMV myself. Idle no longer "rattled" but when driving and braking the idle would drop down very low and sometimes not "kick up" and would die. I then took it back to dealership to have them replace the vent solenoid and reprogram the PCM. Still doing it. They said I might have a defective (new) Idle air control and to replace it- otherwise they dont have a clue.
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2002 Hyundai Elantra GT 2.0L 140k miles
Symptoms:
- Intermittent rough idle when hot, slight shutter, surges between 700-800rmp
- Intermittent hesitation when accelerating, cylinder 2 misfire when hot and under load
- Misfires in all gears under load, mostly when under 2000rpm
- Code P0302 when scanned, no other codes
- Symptoms appeared suddenly, not gradually over time
What's been changed:
- Replaced spark plugs, little or no improvement. Old plugs looked worn, but generally in good shape with no significant deposits.
- Cleared code and swapped injectors between cylinders 1 and 2, after test drive P0302 code came back, so it seems that the injectors are good. If the injector were bad I would have expected the misfire to change from cylinder 2 to cylinder 1.
Inspection and Testing:
- Ignition System Testing
- Spark plug wires and primary coil are within specification.
- Secondary coil resistance is high on both packs. Could this be causing a problem with just cylinder 2? Is it worth replacing?
Spark Plug Wires: Specification: 5.6 Kohm/meter +- 20%Cylinder 1: 2.49 Kohm (Longest)Cylinder 2: 2.03 KohmCylinder 3: 1.64 KohmCylinder 4:1.36 Kohm (Shortest)
Primary Coil: Specification : 0.58ohms +- 10%Actual: .6 and .6
Secondary Coil: Specification: 12.2 Kohms +- 15%
Actual (Cold): 16.03K for Cylinder 2-3 pack and 15.94K for Cylinder 1-4 pack
Actual (Hot): 18.54K for Cylinder 2-3 pack and 18.44K for Cylinder 1-4 pack
Air/Fuel System Testing:Fuel system seems to check out. I do not believe the problem is fuel related. There are no obvious cracks or leaks on the intake manifold. A good spray of Carb cleaner all around the manifold causes no change in idle. I might try propane later. No obvious vacuum leaks.
Fuel Injector: Specification: 13.1-14.5 ohms
Actual: Cyl 1: 14.9, Cyl 2: 15.3, Cyl 3: 15.3, Cyl 4: 15.7
Compression Testing:Compression is not great, but within specification. Could the slightly lower compression in Cylinders 2 and 3 indicate a head gasket leak between those cylinders? Could this cause a misfire in Cylinder 2?
Dry Compression: Specification: 145-218psi, <15psi between cylinders
Actual: Cyl 1: 165, Cyl 2: 155, Cyl 3: 155, Cyl 4: 160
Oil/Coolant/Tailpipe:
- Oil looks normal, not brown or milky
- Coolant looks normal and is full, no signs of leaking (coolant has not been changed in a very long time, could a coolant flush work?)
- Exhaust looks and smells normal from tailpipe.
Sticking valve? How would I check this? Bad sensor somewhere? Doesn't a bad sensor usually throw a code?
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I have a 2013 Golf TDI with 2070 miles on it. For around 2-3 weeks, I've noticed that it intermittently will idle rough, shakes, etc, as if it is about to stall out, but stays running and drives normal. I figured it was a typical Diesel thing and wasn't too worried about it. However, today, this happened, and I got an engine light. Yikes! I made an appointment for it but need to wait till after the 4th for it to be looked at. What's up here? Is it a regen cycle? Timing issues? Am I doomed with my Golf TDI?
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My g/f's 2004 Ford Escape (3.0L V6 AWD 112,000mi) is acting up. After a full day of sitting, with the second half of it raining steadily, she was driving her Escape and it was acting funny (miss-firing, she said). The engine light came on and soon began blinking. She got to my house shortly after it started this. We left it and I drove for the day. Later that night, I drove it and it seemed fine. The engine light was on, but not flashing anymore.
The next day I took it my friend that was a Saturn mechanic and now working at a KIA dealership (same owner as the former Saturn and current Buick/GMC and Chevy Dealer). It ran fine for me. So he tries to scan it, his Mac Tools scanner won't read it. The KIA scanner wouldn't read it. I drove it the Ford dealer up the road. They said they couldn't get to it until after lunch, I just want the codes read. They re-iterated, and I told them to pound salt and went to an independent shop where I know a guy. They read it right away for me. "Mis-fire on start-up" & "Cylinder 4 Mis-fire." were the two codes stored. He cleared them.
She got the tune up basics (plugs, wires, air filter, etc) and did the complete tune-up herself yesterday. (I was impressed). She put 94 in the tank and some fuel system cleaner in it as well. She said there's been no change and today I finally saw what it was doing. Sometimes during idling at a stop light, the RPMs will drop to almost zero, the lights dim but so far it has not stalled. It'll do this for several seconds, then correct itself and idle normally.
Currently, the engine light has not come back on. She's thinking coil pack (each cylinder has a coil on these engines) on #4. She wants to switch it out with #1 and see if the problem follows. I think that might uncover the cause, or it could be the battery. It's the original, never been replaced and has a lot of miles on it, but it survived this past winter, without trouble. In my experience, most batteries crap out due to age in the fall when the cold snaps start.
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I've been experiencing an annoying intermittent condition on my '07 Sonata (Lambda V6). I wanted to share this in case any of you are experiencing intermittent rough idle complaints in your Sonata (4G) as well. I was finally able to get it into the dealership during the malfunction; in my case, the MIL never lit. Here are the symptoms: ONLY after being fully warmed up, when coming to a full stop, or using just idle speed to, for example, pull into a parking space, or inch up to a stoplight, I would experience a very rough idle (I could hear the engine sputtering with the window down), see the RPM gauge bouncing, and feel the vehicle going "putt-putt-putt" as it tried to keep running under what seemed to be a misfire or too much load. The problem occurred more noticeably with the A/C off but still did occur with it on as well. While exhibiting this problem, acceleration from a stop gave a slight hesitation as well, but once going faster than 1,000RPMs, the problem went away totally. I thought it must have been my imagination until one day, I pulled up in front of a glass window and could see the reflection of my car lurching forward as it struggled to keep idling. Getting it to the dealership while it was behaving badly was the hardest part.
Once I got there, I got a tech to ride with me and finally, after 3 visits to the dealership, someone else witnessed the problem. Up until now, I've been asking people, "Do you feel/hear that?" "Huh?" I digress... The tech immediately said he thought it was a power steering issue and he thought there was an upcoming bulletin on it. I was sure he was wrong, I was thinking it had to be the spark plugs, wires, MAF, or TPS.
After getting the part in for me (Power Steering Sensor Switch) they put it in today and my vehicle is just as new again. It was never a serious issue, but was rather embarrassing to try and show off my Sonata and have it stutter and sputter like that it idle.
This part is complete speculation; maybe a more knowledgeable person can jump in here and correct any logical errors: Apparently, there is a switch in the Power Steering Unit that detects highway speeds versus slower speeds. When vehicle speed is above a certain limit, the power steering pump is either turned off or "turned way down" (so people get the stiffer feel of the wheel at highway speeds). When the vehicle slows down to idle (to be detected by this switch), the vehicle expects the power steering pump will draw full power from the engine and needs to have a slightly higher idle speed to compensate for the load. My switch was malfunctioning; it was not registering to the ECM that the power steering pump was under load when it actually was; the vehicle then did not bump up the idle speed appropriately, and thus, the rough idle and hesitation.
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For the last couple months I've been messing with a P1118 code. Started a few months ago when I noticed my fuel mileage was down 1-2MPG. Also sometimes a rough seeming idle (hard to tell with the diesel). Then it threw a P1118, so I replaced the temp sensor under the turbo. The code went away for a while then came back, fuel mileage didn't change. So I replaced the temp sensor in the air filter box.
The code went away AND my fuel mileage seems to have come back to normal. Now, code thrown again. Search on P1118 hasn't been super useful. Seems like replacing the sensor under the turbo is the trick. Also seems to come up in combination with a bunch of other codes with battery problems. I suppose it's possible I have some sort of electrical gremlin. It throws the code on startup and stays on until I shut it off. Doesn't come on every time, is off more often than on.
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Still showing the same codes (per repairman) and still having the intermittent rough idle at low speeds when the engine is warm. It has been so intermittent that I could almost live with it.
So repair guys first replaces the VCT's and runs fine until warmed up and the problem reoccurs with the same codes. He replaces both cam phasers and tensioners today and still same problem and same codes which point to the VCT and cam phasers.
Truck has 80k, city driven, oil changed every 3k or so. Burns ethanol and still runs great at speeds over 10 mph even when this problem appears.
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When starting your SC on let's say a day where the temperature is 35 - 55 degrees, what is your initial idle RPM?
Next, how long does it take to settle down to a lower RPM and what is lower RPM when the car is still in Park?
Lastly, can tapping the gas pedal after initial start-up bring the idle RPM down while the car is in Park?
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I took my car to a mechanic the other day to get the spark plugs change. Then I notice when I turn my car on my seats starts to vibrate when in idle. Is this normal cuz the mechanic says this is normal and that every car vibrates just a little. I read some where it could be the mounts but someone on here told me they not because it doesn't shake my seats just vibrates if I seat there I can feel the seats vibrating on and off its not crazy bad vibrate. It's a minor vibration. I was hoping for no vibration what so ever like sitting in on my leather couch in my living room. Mine is a old model 2002.
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