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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15201
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I have a customer with a 2005 Tahoe 5.3 and it came into the

Customer Question

I have a customer with a 2005 Tahoe 5.3 and it came into the shop because of a weird exhaust smell. Upon diag, I found cyl#1 misfire. The plugs and wires were original, sowe tuned it up. It made no difference. So I noticed on the scanner that when cyl starts missing, it causes all the other cylinders on that bank to mis as well, but just not as bad. So first I swapped spark plugs over to cyl 2, no change. Then I swapped wires, no change. Next I swapped injectors to cyl 2, no change. Then I swapped coils. No change. I took compression and had 90lbs. I took compression on cyl 2 and only had 80. The engine only has 102k on it. Next I changed the intake gaskets cause it had a po171 and all those cylinders were missing. No change. Fuel pressure is about 60 psi. The weird things is, e, the mis came when you take it out and run it at highway speeds it runs great. But it usually only misses at idle. Right about 590 rpm. I was thinking it could be loaded up with fuel cause of the black crap coming out the exhaust, so I took it out again and ran the puss out of it. At wot it runs great but when I got it back to the shop and let it idle, the miss came back. Starting with cyl 1 thus causing all the other cylinders on that bank to start missing. What the hell am I missing??? Any info would be appreciated
Submitted: 1 year ago.
Category: Chevy
Expert:  Lou P. replied 1 year ago.
Hello my name is ***** ***** i will do my best to help you , i strive for EXCELLENT service and nothing more. What is the self adaptation at at idle ? Or fuel trims ? On bank one and two? Also have you tried to perform the crank relearn ? How dirty is the throttle body ? Have you tried to clean it ? What was compression on ALL cylinders ?
Customer: replied 1 year ago.
I did not do a crank relearn, and I did not do a compression test on all the cylinders. I will look at the fuel trims in the morning. I've had enough for one day. I'll get back to you. Thanks
Expert:  Lou P. replied 1 year ago.
Ok. Thanks for replying.