Question5.7L TBI, will die intermittently when stopping and/or turning at low speed, usually with foot on the brake. Sometimes you will feel it start to die and give it a little gas then it will stay running. When it dies, place it in neutral and it starts right back up like nothing is wrong. Have replaced TPS, cap/rotor, ignition coil, mag-coil(?under rotor), ign module, fuel pressure regulator, fuel filter and battery cables. Ign module died on the road costing me a tow bill. All the other parts were replaced as routine maintenance or were borderline when tested except for regulator that was replaced at recomendation of a local mechanic. Plugs and wires have very little age on them. Vehicle has over 265,000 miles on it, 115,000 on GM crate engine. ECM was replaced about 3 years ago. It runs better now on the road but still dies! I read some previous posts about the IAC and the air passage to it. The IAC checks ok with a DVM and I have sprayed the TBI with carb cleaner but not specifically into the air passsage, can this be the issue? Is there a better way to see if the IAC is actually working? Can the injectors be tested? I have not done a fuel pressure test, mainly due to it running ok the rest of the time. Looking for any help or suggestions before I throw in the towel and take it to the shop. Am I overlooking something simple? Thanks in advance
AnswerHi,Wendell
I was leaning towards an IAC,this can cause your complaint,GM has updated the IAC to a better design,usually it and that passages get choked with carbon,also dont overlook a vacuum leak,either at the TBI base gasket or the intake manifold gaskets,this will cause an idle stall also.
The IAC is tested using a tester for it,you can find one at the parts store or sears i believe has one,though not 100% accurate,it lets you know if the ECM is doing its job in commanding it.
The injectors can be tested using a DVOM,messure resistance,TBI injectors usually ohm out at about 4.0 ohms.
ED
