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International Automotive Technicians Network
Prev Professional Automotive Repair Technical Discussions for December 29, 2005
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Open Help Requests for GM
Help Request Answers
1996 Buick Century Custom 3.1L Hesitation, Cuts out, Misfire VIN: 1G4AG55M3T
Ok, heres what we got, this car came in 3 days ago with a horrible hesitation, miss, and no power anywhere above idle, under load or in park. It had only 12 in vac at idle, which dropped out as soon as you got to about 1200 rpm and the engine would fall on its...
1999 Buick Park Avenue Ultra 3.8L abs light on VIN: 1G4CU5216X
abs light is on, there are two codes stored in the computer 1235-rr speed sensor ckt open/short 1255-ebcm/ebtcm internal malfunction. i have replaced the rr speed sensor which did not help. i have also used a lab scope to check the waveform at the ebcm harness...
1995 Cadillac Fleetwood 5.7L rear auto level control VIN: 1G6DW52P8S
the rear auto level air compressor runs about every 1.5 minutes for about 3 seconds.the rear of the car drops about 1/8 inch then the pump cuts on.i found a leak at the drier & replaced it. now it turns on about every 4 minutes & the car drops about 1/8 of a i...
1990 Chevrolet Lumina 3.1L No Start, Stall VIN: 2G1W54T1L1
thought i had this fixed i found a Bad ground to the ECU repaired the ground and it ran for one hour so i released it to the customer after 4 days they brought it back with the same symptons runs for 5 min then dies and won't restart until it cools down. ECU i...
1997 Chevrolet Astro 4.3L No Start, Surge, Stall, MIL Lamp on VIN: 1G45S8TW8A
OK!!! about a month ago this van came in on a hook.. did a tune up, fuel filter and it ran like a champ.. next day couldnt pull itself. checked egr, check all sensors, everythink looked ok. shut it off and started it good as new??? why I dont know... customer ...
1997 Chevrolet C1500 4.3L No Start VIN: 1GCEC14W5V
Have lots of fuel and spark at plugs. Plugs foul out as soon as key turned on. It does not even try to start. Customer has tried AC Delco crank sensor and ignition/coil control module as well as new coil. I don't like crk sensor signal strength but it may not ... Trouble codes: P0300 (random Misfire)
1998 Chevrolet Prizm 1.8L Poor Idle Quality, Hesitation, Surge VIN: 1Y1SK5281W
I have this prizm that has a high idle with a/c on (1400 rpm), and normal idle with no a/c (860 rpm). While driving at steady throttle it will have a surge or hesitation that seems like fuel or spark is cutting out for a fraction of a second. I can't figure wh...
2000 Chevrolet Silverado 2500 6.0L Lifters? VIN: 1GCGK24U3Y
Hi all, It's always something new. This engine has a very loud click, like a lifter, but only at 2000 rpm.. its starts to make noise at 1900 rpm and fades away above 2100 rpm. This makes me to think that it has a valve train problem, maybe a weak spring.. When...
2001 Chevrolet Silverado 1500 4.8L Hesitation, Misfire, MIL Lamp on VIN: 2GCEC19V61
this vehcle came in for missfires under load, has lots of miles, inside the throttle body i could see lots of build up so i performed a bg induction clean, also a fuel injection service , vehicle seems to have huge spark knock at cruise, fuel pressure seems to... Trouble codes: P0300 (multiple missfire)
1996 GMC Sonoma SL 2.2L Hesitation, Stall, MIL Lamp on VIN: 1GTCS1446T
The problem I am having with this GMC is the 5V-REF. voltage to the sensors is only 2V-REF. Voltage to the computer is battery voltage (good) grounds to the computer are also (good)Replaced the computer and still having the same problem. Any one run across thi...
2003 Hummer H2 6.0L Misfire VIN: 5GRGN23U43
Hi all, Thanks in advance for any help, this Hummer H2 is misfiring on bank 2. Cylinders 2,4,6,8 are showing misfires on our scan tool and this vehicle runs like it too. The fuel pressue is 55 lbs. the compression is 125-130 lbs all the way across, we have s... Trouble codes: P0300 (Misfire code)
1992 Oldsmobile Custom Cruiser 5.7L Excessive Emissions VIN: 1G3BP8373N
Vehicle came in for failed IM240,H.c.failed slightly 0.800 gpm limit and was 0.875. and I contributed that to carbon deposits so gave it the G.M cleaner and let it soak overnight,but have not pursued that portion any farther,Knowing the N0x failure was most li... Trouble codes: 32 (EGR system error stored but did not have check engine light oncode has been cleared and has not reset as of yet.)
1999 Pontiac Firebird 3.8L Misfire VIN: 2G2FS22K1X
Vehicle came in with a noticeable miss whether at idle or driving, hot or cold. Scanned computer and retrieved code for misfire, so I watched the datastream and found #5 missing quite often and number 2 every so often. I pulled the number 5 plug and it looked...

Fixes & Summaries for GM
Fix/Summary Answers
1997 Buick LeSabre Custom 3.8L Fuel Guage VIN: 1G4HP52K8V
Well, I am really embarrassed to report the details of this fix, but it may save someone else some trouble some day. When the car came in it originally had a code for the map sensor. I went thru all the tests and it was dead with no response to vacuum at all. ...
1991 Cadillac Seville 4.9L No Power VIN: 1G6KS53B7M
Vehicle turned out having 2 promblems. First being a vacuum leak at the manifold causing low vacuum to the map sensor which controls many of the vehicle settings. The second problem was a blown injector fuse. Vehicle runs good now. Thanks for everyone's sugges...
1994 Chevrolet C1500 5.7L Surge, iac code 35 VIN: 2GBEC19K8R
i was told by a number of techs to inspect the gasket below the throtlebody housing unit. unfortunately the customer pickt up the truck so we will have to try that on the next visit he does with us.thank you all for your hellp,will keep you posted on this. Trouble codes: 35 (iac problem).
1996 Chevrolet Tahoe LS 5.7L Drive Line VIN: 1GNEK13R2T
After running vehicle without driveline, and triple checking all rear end bearings and gear wear pattern, seemed to be coming from transfer case, pulled case inspected nothing seen, reassembled informed customer that it must be something in the rear of the tra...
1997 Chevrolet Tahoe LS 5.7L alternator VIN: 1GNEK13RXV
WAH LA, I FINALLY FOUND IT. Someone had placed a F@#%$^G paper clip from the alternator field wire to a separate 12 volt supply behind the instrument cluster wiring connector. I had voltage present at the field wire that was not being shunted by a bulb... the ...
1998 Chevrolet K2500 Cheyenne 5.7L clunk VIN: 1GCGK24R2W
After disassembly, I found the sprague on the direct drum wouldnt hold. I replaced the sprague, and all is perfect. Thanks for all of the replies.
1999 Chevrolet Blazer 4.3L Poor Idle Quality, Hesitation, Misfire, MIL Lamp on VIN: 1GNCS13W6X
Hi all you Chevy Tech , Thank you for helping me repair this truck. What most of you said the distributor was out of sync some one had the dist out? set up and reinstalled dist, now runs great, good start up. One of you said fuel pressure, truck runs great, so... Trouble codes: P1347.
1999 Chevrolet K1500 LS 5.7L Cuts out, Stall, MIL Lamp on VIN: 1GCEK19R2X
Well I think this one will be back, but for now it's running ok with no mil on for him. I was waiting for him to run it low on fuel so we could replace the pump, but he decided he didn't want to replace the pump just as a precaution. I told him I needed the mi... Trouble codes: P0453.
2000 Chevrolet Blazer LS 4.3L Hesitation VIN: 1GNCT18W5Y
Hello everyone turned out the pressure gauge was reading wrong. It was a digital snap-on pressure gauge, and the wires werre getting bad connection moved wires near pressure fitting and pressure jumped up around 58 psi. So fuel wasant problem ended up being a ...
2001 Chevrolet Silverado 1500 5.3L dic VIN: 1GCEK14T71
I want to start by thanking all who responded. The general idea is that the system is flawed. But, if you run into one the possibilities can be a programing update available at the dealer only, try pressing the accelerator 4 times instead of 3, check to see if...
2001 Chevrolet S10 4.3L Excessive Emissions, Poor Idle Quality, Misfire, Poor Fuel Economy, MIL Lamp on VIN: 1GCCS14W61
removed all spark plugs left for night-next morning cleared cylinders of fuel vapors - reinstalled plugs- changed oil and filter- truck started right up- but fuel pressure still droping with engine off- diagnosed bad check valve on fuel pump and pump very nois... Trouble codes: P0300.
2002 Chevrolet Silverado 1500 4.3L Misfire, MIL Lamp on VIN: 1GCEK14W72
I would like to Thank Everbody for there replys as the the answer was there in the emils the dis. drive gear was worn like a knife blade and no 3&4 the sharpest new gear no problum THANKS TO ALL OF YOU HAPPY NEW YEARS Trouble codes: P0300.
2005 Chevrolet Silverado 2500 HD 6.6L fuel knock VIN: 1GCHK29235
well it is fixed. the final repair was cheap and easy. however the road to that point was rough and slow. basically there was a problem with the fuel. there was no water in it. the api reading was good. it was in fact diesel fuel. we installed wynn's diesel fu... Trouble codes: P0308.
1996 GMC K1500 Sierra SL 5.0L Excessive Emissions, MIL Lamp on VIN: 1GTEK14MXT
To everyone, thanks so much for your help and suggestions. it did end up being the regulator leaking. Again Happy holidays and Thanks sooo much for you guys taking the time to help a fellow owner/operator. And, IATN what a great resource and tool! Mark Darri... Trouble codes: P0172, P0175.
2000 GMC Sonoma SL 2.2L Lack Of Power VIN: JGTCS1955Y
Well this one is Fixed with a New Engine. We never were able to determine what was wrong with the last one. We are guessing that the cylinder head from the 00 on the 96 Block must be differant causing low compression. Thanks for the replies
2003 GMC Yukon Denali 6.0L speedometer VIN: 1GKEK63UX3
thanks to everyone who helped, i told the customer when he picked it up it probably had a problem with the cluster, by all the replys, i think i will send it out for repair. thanks again, jason [...].
1989 Oldsmobile Cutlass Calais 2.5L Hesitation, Stall VIN: IG3NL54U7K
Thank all of you for your help. I finally got this one fixed. the biggest problem I had was that nobody had parts in stock. I had to order almost every one and wait 3 to 7 days each. First, the hesitation and backfire was #1 spark plug wire arcing to groud u... Trouble codes: 45 (Rich Condition).
1991 Oldsmobile 98 Regency Elite 3.8L No Start, Hesitation, Cuts out, Stall, Misfire VIN: 1G3CW53LOM
Thanks to everyone that replied the suspect part was the maf sensor. I think the ignition module was also to blame with the no spark issue when it first came in. This mourning I got it to run long enough for it to go into closed loop and the maf sen readings w... Trouble codes: 13 (02 sensor), 22 (tps low seems ok now), 23 (iat was unplugged), 31 (park neutral fault), 43 (esc fault).
2002 Oldsmobile Bravada 4.2L MIL Lamp on VIN: 1GHDT13S12
Thanks to those who responded. We have talked to GM, our Vetronix and Tech 2 rep and many others and have not found a way to reprogram PCM due to EX at end of VIN #. These vehicles were manufactured with this VIN so at this point it appears unlikely to make th... Trouble codes: P0495 (fan clutch locked).
1996 Pontiac Grand Am SE 3.1L starts and dies VIN: 1G2NE52M7T
Theft module in instrument cluster bad- Replaced cluster.
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