Yukon :: 1999 - GMC Suburban K1500 5.7L Misfiring / Lopes At Idle / Stumbles Under Load
May 4, 2009
I had to choose the Yukon, as there is no Suburban?
Anyway, I have a very bad misfire in my truck. Lopes at idle stumbles under load. Through substitution, I have tested: module, coil, and crank sensor. I have replaced: plugs, wires, cap, rotor, air filter, fuel filter and upgraded from SCFI to MFI (can you say "expensive best guess"?).
Still getting P-0300, P-0302 and mostly P-0304, using a Snap-on Modis scanner.
Compression tested today: all cylinders between 160- & 170 psi. After this, leak-down seemed redundant.
Back pressure test: 0.5 psi at 2500 RPM, both banks.
Steady fuel at about 60 psi.
I am going to pull distributor (175K miles) and examine drive gear. Not too sloppy at rotor bearing. However, how do I set baseline timing when I re-install distributor? If the distributor is OK, what test or part should I look at next?
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I have a 98 k1500 5.7 vortec. I was driving and the next thing I knew my truck lost power and would misfire at an idle but only when under a load (in drive with foot on brake). The last time something like this happened an injector came out of place. So that's where I started. I wound up changing the whole spider injectors and ALL the gaskets, upper and lower. I put everything back together and the problem was still there so basically I am back to square one.
I then pulled spark plug wires while running to see if I could isolate the misfire and found that I could pull all 4 wires on the passenger side without any difference in while it was running. So basically my truck is currently running on 4 cylinders and they all happen to be on the driver side. I checked my compression on the passenger side and all 4 cylinders have 180 psi so that rules out the head gasket being blown. I am getting 4 codes , 520, p1345, p0155 and p0161. I know that i have to get tge truck properly timed with a computer but i don't think that would cause my problem.
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'99 K1500, 5.7L, 130K miles, regularly serviced and well maintained, no garage so sits out in weather. About 8 months ago we started to experience no starts after rains, engine would fire off, but not stay running, security light NEVER came on. Took to regular mechanic and had fuel pump replaced (needed it anyway), wiring "repaired" behind dash. No problems till last month, then same started again. Sometimes will start after 5-6 tries, other times will not start till 10-12 hours AFTER rain stops.
Security light came on ONCE while driving for 5 minutes, then went out. TSB's indicate possible corrosion in the Passlock sensor voltage, underhood or under body connections, may be reason. Where these are as I would prefer to check them myself to see if simple solution before pay mechanic to find the same. Since did not reoccur for a while after fuel pump replaced, are there connections that would have to be pulled to replace tank that may now be not sealing again with time? Any resource for wiring diagrams for Passlock path?
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1999 gmc suburban shut off no start next morning will crank then act's like it loads (cranks hard for a second then back to normal) has good spark has a fuel vapor out of exhaust but will not fire.
What I've checked
Spark on every plug. Good and new
When I pulled the plugs they were wet with gas
Distributor turns new cap & rotor
Checked time manually (TDC looked at distributor rotor Pointing cylinder at # 1 cylinder
Will check fuel pressure when I get home
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I have a 1995 suburban k1500 4x4 i just pulled a check engine code 35 what could be causing it to appear? I need to know if its something small or a big fix?
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1999 Suburban 5.7L Vortec
Symptoms: While driving after engine warm-up the engine misfires on cylinder 2 under slight load (basically whenever maintaining speed, and slight acceleration) between 1500-3000 rpm's. Backfires through exhaust when this is happening. Misfire counts on Cyl. 2 collect rapidly and only a few on Cyl. 1 but no P0301.
History: Purchased vehicle with a blown engine (intake gasket leaked coolant into engine and was hydro-locked) with the intention of using it to pull a boat or camper but never did buy either one. Replaced the engine with a new Goodwrench engine and rebuilt the tranny figuring I would drive it till the body rusted off of it. I honestly never felt that the truck ran as strong as it should have with a brand new engine but just attributed it to being as big as a cruise ship. A couple of years later started receiving multiple codes (don't remember what they were at this time) found the distributor very corroded inside due to the ear on the distributor being broken off.
Replaced the distributor, cap,rotor,plugs and wires and fixed it. About a year later, only in the summer I would start to receive the P0302 sometimes, would not happen in the winter. Did the usual plug swap, wire swap, checked spark to rule out ignition with no change. After a while the catalytic converter failed (big surprise with a missing engine) and replaced it as well as both O2 sensors on the rear bank and one on the front bank. P0302 did not change. Last year the fuel pump failed so I replaced it. This April I took the truck on a road trip to visit relatives, about 80 miles out it started backfiring through the exhaust whenever I got over 70 mph and the CEL would flash. Finished the trip babying it the whole way but now it does this all the time when warm.
Repair attempts:
* Distributor, cap, rotor, wires, plugs. (Due to distributor failure mentioned above.)
* Fuel pump and filter. (Due to pump failure mentioned above.)
* Upgraded fuel injection spider. (Because of GM bulletin regarding misfires and multiple failures found on the internet.)
* Repeated valve and fuel system cleanings. (Grasping at straws.)
* Removed rear bank cylinder head and sent to machine shop, All checked good. (After ruling out ignition and fuel figured it had to mechanical. Compression was good, cylinder leak down test was good. The problem seems to be temperature related so thought maybe the exhaust guide was mis-manufactured too tight causing it to drag when warmed up.)
* Crank sensor with a used one from a u-pull it place, I got too much money wrapped up in this. (Found a reference to this repairing a similar problem on another vehicle.)
One final note: After replacing the fuel injection spider the truck ran extremely well, this only lasted a few days and the problem came back. After replacing the crank sensor the truck again ran extremely well, but only for 1-2 days. What is the connection between the injection spider and the cranks sensor? The only other thing that I can think of that would create a misfire on one cylinder only is the PCM but that gets misdiagnosed so much that I don't want to jump to it unless all other options have been checked out.
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I'm working on a 2003 Gmc yukon xl, which is the same as the suburban. Check engine light is on and the codes P0220 (TPS sensor) and P1518 (TAC throttle actuator control) are on. I've cleared both codes drove the vehicle all day, but when I shut it off and start it back up the two codes are back on and a message on the dash says reduced power, and there is no throttle. However if I clear the codes everything goes back to normal until I shut the thing off again and the 2 codes pop on and it says reduced power... Now I've cleaned the tps sensor electrical connector thinking this was the problem, but no luck.
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So basically I thought it would be a great idea to degrease my motor from the top down.... After washing I start it up and drive down the road to head abunch of misfiring under heavy load or high rpm's.
My problem is that the misfiring won't throw a code. I then proceeded to buy a new ignition coil (thinking this was the problem) but with no code to go off which cylinder was bad I just switched the good ignition coil into each cylinder and starting it.
Up each time. None of them seemed to make it better. Also the injectors all seemed to be good. So what to do ?
2002 Ford F-250 5.4l
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I have a 2000 VW Passat with the 1.8L turbo. When I bought it, the timing belt was off 1 notch. After I fixed the timing issue the car still didn't idle well. I was told that the throttle body was causing the problem so I replaced it. The car ran good for about 5 minutes after I replaced the throttle body. After I hooked up a OBD-II scan tool up to it instantly started running rough. The car runs at 1100 rpm at a cold start-up but when the car warms up it idles down to 850 +-75 rpms. I cleaned the MAF sensor, and it still runs rough. Car has 180,000 miles and MPGs are also down.
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'91 buick, 3 spd. 0 acceleration in 3rd, trouble code says TCC curcuit. Lopes @ idle when warm, runs rough @ times. many new sensors, timing chain & sprockets, still, the loping.
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I have a P2195 and P0171 ... 2006 Ranger 2.3 ... Drives fine but at idle..idle gets slower till it lopes. Changed O2 sensor,Cleaned air flow sensor,changed PCV valve, Can't find any leaks, could it be EGR...how do I check it ?
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I have a 03 Suburban LT with the 150,000 miles. and it misses out at 50mph or higher. I thought it was the transmission, and the tranny guy confirmed a new transmission was needed, but said he thought the missing was maybe the coils. the local Chevy dealer did the diagnostic, and determined the coils, plugs, and plug wires were all good. I 've replaced the oxygen sensor as well. The service manager said to keep driving it until the Check Engine light comes on. That concerns me, but hey what do I know. The mileage hasn't dropped off, and it runs fine the rest of the time.
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97 chevy k1500 with 305, engine rebuilt by shop 60k ago, last few months only drove truck 4-5 times, last time driving gave p0306, new plugs, wires, cap, rotor, cleared code, now gives p0300, took intake apart removed spider, sprayed/scrubbed each injector and poppet with cleaner, but no way of cleaning the line between the injector and poppets. No change after cleaning. Also ran injector cleaner through tank. All vacuum hoses look in good order, sprayed carb cleaner around intake to check for leaks at intake/throttle body, no leaks.
Checked TPS, IAC, MAF, Coil and fuel pressure, all good except fuel pressure was 52-54 while idle, replaced fuel pump, screen filter and main filter, cleared code, rough start and rough idle still gives p0300. Checked coil with ohmmeter, between posts A & C, Chilton says 0.1 ohms, i got 0.5 ohms, went to autozone and had them check a new coil, it have 0.5 ohms......? Can drive at higher speeds and runs smooth, but idle is poor almost dies.Checked fuel pressure after pump replacement, still ~54 psi. Stumped and don't want to throw more parts at it without a proper diagnosis. Have a OBDII pocket scan tool, but can't find manual, will try to find manual and see if I can pinpoint the misfiring cylinders.
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I have a 2008 Passat Komfort Wagon with the 2.0T. At 40,000 miles, yes it only has 40,000 miles, the thing started hesitating and misfiring on me only during heavy load. I ran the codes and it said #4 cylinder misfire. The check engine light was only on during the time it was misfiring and hesitating. Took it to the VW dealer to have them run it again and get guidance and they verified the #4. When I picked up the car the CEL was illuminated. They said it does it when it misfires. I explained that it was not on when I dropped it off and they basically said tough cookies. So I replaced the #4 coil pack and all 4 plugs. CEL light still on, but wasn't misfiring. Next day it began misfiring again under heavy load. Took to Autozone to run the codes and now says misfiring on all cylinders.
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I'm getting misfiring after the engine is hot, but it only shows up under certain load. For example, if I'm in 3rd gear at about 2500 rpm and I give it some amount of throttle, it wont misfire at all but if I give it just a hair more (maybe past 50% or so), it will start misfiring badly and the blinking CEL comes on. The codes it's triggering are misfire on cyl 1 and multiple misfire.
I replaced the coilpack about 6 months ago, that's why I'm hoping for some feedback before I drop a few hundred dollars on another one. I had the plugs out very recently and they look fine. The shape of the wires are difficult to get multimeter probes on so I haven't checked them.
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I got a 99 1.8t. Here's the deal, misfiring at idle, flashes battery light. alt and battery was checked and there great. it has a maf code, so I unplug the maf and still get the same misfiring. maf was fine be4 i tried cleaning it, now it throws the code. it had misfiring be4 i clean it also. next problem is it stutters and misses if i go wot in 4 or 5 gear and the batt light flashes it doesn't throw a misfire code. Also if I am idling and i floor it, it stutters and misses at lower rpm rage and then is fine at higher rpm range. i replaced plugs and gapped em right, i did a power balance test and the coils all are firing so is the injectors. I don't got vag but i do got a good obd2 scanner i was looking at the data wen car was off and i seen that if i floor it the tps only reads 77.7% . Also my timing says its 12 degrees and idle fuel pressure is fine i checked with a gauge. Pretty much misfiring with no codes thrown and flashing battery light.
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My 99 Explorer XLT V6 SOHC has been misfiring lately. In idle the RPM needle fluctuates a bit and the vehicle vibrates and shakes. At night when the lights are on I notice them dim a bit as the engine struggles in idle. It doesn't stall very often at all. Accelerating I notice way less power and the engine studders. That's when the engine light comes on flashing. Then remains on solid afterward. I brought it to a mechanic friend who read the code and it was cylinder two misfire as well as the O2 censor.
I replaced the plugs and leads and censor. Noticed the plug in cylinder two had little to no gaping. Thought I had fixed the problem. The vehicle ran perfectly. Three or four days later driving on the hwy same problem came back. Thinking it must be the coil pack I got one for a good price and replaced it. Again, the truck ran great for four days and now the problem has returned. Same thing, shaking studdering and flashing engine light. I have verified the locations of the wires and plugs a few times so i believe they are all properly installed.
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My 99 Explorer XLT V6 SOHC has been misfiring lately. In idle the RPM needle fluctuates a bit and the vehicle vibrates and shakes. At night when the lights are on I notice them dim a bit as the engine struggles in idle. It doesnt stall very often at all. Accelerating I notice way less power and the engine studders. Thats when the engine light comes on flashing. Then remains on solid afterwards.
I brought it to a mechanic friend who read the code and it was cylinder two misfire as well as O2 censor. I replaced the plugs and leads and censor. Noticed the plug in cylinder two had little to no gapping. Thought I had fixed the problem. Vehicle ran perfect. Three or four days later driving on the hwy same problem came back. Thinking it must be the coil pack I got one for a good price and replaced it.
Again, the truck ran great for four days and now the problem has returned. Same thing, shaking studdering and flashing engine light. I have verified the locations of the wires and plugs a few times so i believe they are all properly installed.
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I recently purchased a 2000 7.3, when it's started cold it's lopes at start up unless I give it some gas and then it's perfectly fine. If the truck is plugged into the engine block heater it starts normal. I changed the oil the day after I bought it and put 15w-40 in it and then the rough idle started. So I don't know if it was like this before or because of the thicker oil I put into in the cold. It also has a service engine soon light on and the code that comes up when read is to the icp sensor. When looking st the sensor the blue wire going to it looks cut and is disconnected. How would I reconnect these wires and see if that makes the check engine light go off.
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I have a 2002 F250 CCSB Lariat 4x4 with the Triton V10, I'm up to 232,000 miles so far and fairly happy with the old girl. Just this weekend, I noticed some hesitation when at idle and even more rough running when under slight load. The misfire/hesitation is worst when going up a slight hill, when the truck is accelerating at low RPMs.
I am getting zero trouble codes or freeze frame conditions on my scanner. What should be my order of diagnosis? Vacuum test at line from PCV to TB, COP test? EGR inspection? Plug inspection? Also, how do you test a coil if resistance is not a reliable method?
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I have a 04 FX4 scab with a 5.4L and am having issues with it idling rough, and low power and stumbling upon acceleration and cruising speed. I did a scan and the codes show lean run condition, misfire on cyl 4, etc. I changed injector and coil on #4 and it seems worse. Scared to change the plugs, until I can leave the truck down a day or two in the event that I break one or more.
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