Hi there, looking for some advice. I have a 2001 Camaro V6. Recently had an O2 sensor replaced due to trouble code plus rough idle and intense bucking / hesitation when accelerating at low-mid speed ( apprx 2nd / 3rd gear). It ran smoother but still a little rough idle and slight bucking so had spark plugs replaced ( it was time anyway ) and mechanic also replaced fuel filter and said old one was very dirty. (Power steering was leaking so hose also replaced. I know it's unrelated unless it may have splattered on something nearby that could cause these issues?) After that it ran smoother but still slight bucking and now repeatedly stalling at idle. At red lights, or if coasting real slow ( just edging forward in a parking lot for example ) the power cuts out so silently sometimes I didn't even realize it stopped running. It's idling at about 750 at the red lights. So far, if I apply some gas to bring it up to 1000 ( with foot still on brake ) I avoid stalling. It's not throwing any codes and shows no misfires on my scanner. Mechanic says they can try replacing throttle body but no guarantee that will fix it. This seems to me like an expensive place to start? After reading forums I see there are many other less expensive things to investigate, i.e. sensors (maf, cam shaft position, etc), increasing idle, cleaning out throttle body, fuel systems / tank, etc.

The advice I want is, which items would you investigate and in which order? I have a code scanner and am handy but by no means am I a mechanic or electrician so it's likely going to end up with me going back to mechanic. If so I want to be able to hand them a list of things to check in a precise order, so as to save time and money. Thanks for your advice.

 

Check the wiring harness that goes to the TPS, igntion coils, Air intake temp, coolant sensor etc. The one in the front of the engine. I had a start no run condition/loss of power due to those old wires shorting to one another.
Edit: this happened on my 3.4 94. Not sure if the wiring harness if too similiar on the 3.8.

 

Thanks Corey. At the time you replied I already had the car at a different mechanic. He cleaned out the throttle body which stopped the stalling, but he noticed low coolant without any visible leak plus white exhaust which points to a worn head gasket. During highway driving it ran poorly and finally threw out a code for the MAF. He used an additive to patch the gasket and replaced the MAF. So far so good- no stalling or bucking, but I just got it back so I'm keeping an eye on it. It's still a bit loud at idle (a slight rhythmic revving sound and the oil pressure needle jumps around a bit). If it's still buggy the wiring could be a good place to start.

 

Putting stuff in to seal head gasket rarely works long and can hurt the motor in other ways. Plan on doing head gaskets soon check your coolant and oil every day. If the oil starts to get brown/milky do NOT drive it. Tow it to the place doing the head gaskets.

Make sure the mechanic that is doing the work know it had a head gasket sealer in it as it will need flushed. If your mechanic did not warn you about that the sealer was bad for the engine find a new mechanic. The only time I put that in a customers care is when they are traveling and just need to get home. They knew a new engine may be needed on the other end.