Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Hello you are saying that you have a dead skip or miss in emgine, and it want idle. Tell me about what tools you hAve do you hAve a scantool? Fuel pressure gauge, voltmeter? Does the skip go away with rpm or under a load? Do you know what cylinder? Do you have a VAcuum gauge
Try disconnecting both battery cables tie then together for few minutes then reattach and crank thr vehicle at no point do you touch the throttle. If you have to restart it's okay let it crank and run on own after a minute drop in drive foot on brake and have no accessories on then after idle evens out test drive
Do it exactly like that it should take care of you
I know it's aggravating but in extreme cases it has to be done several times. Try it a few more aND try driving it for a few miles after doing it. Let me know in the morning. Sleep well we get it tomorrow
Okay I'm sorry it didn't work that is best idle learn procedure. Did you say you have replaced iac valve? And you replaced head gaskets, do we know the valves are adjusted properly? I would like to know the fuel trims in the data. Do you have a scan tool? VAcuum gauge?
Yes sir they make scan tools for obd1 I have one. What about vacuum leak? And you could have a bad iac I've had that.
Okay I agree with you. Sounds like you may have a bad Drop the ecm down its behind the glove box and check powers and grounds. I know yo I have checked for codes it would really help if we had a scan tool that way we could confirm no vacuum leak and also tps and other sensors aren't causing problem.
I have though about it and don't know a cheap way for u to get scanner. One thing u could do is unplug each sensor one at a time and see if the idle straight out. The reason I thought ecm is you said the relearn. Would work for min and then revert back. One thing we use to do and don't laugh was called the "tap test" drop ecm down and with it running take the ooen part of your hand and slap the ecm pretty good if it cuts off or changes running at all its bad
Have you installed the ecm yet? I hope and feel like that will take care of your problem.
Good to hear from you, Sounds like you have found the problem but you say you replaced the booster and same thing. That is interesting. And you close the line off no issue so we know we are losing vacuum in that booster, let me ask you when you undone the master cylinder from the booster was there fluid there? Maybe master is leaking brake fluid in booster causing leak? another thing comes to mind perhaps brake switch or cruise switch are adjusted to tight putting slight pressure on booster causing it to operate when at idle? Make sure pedal is pulled all the way back up, good job on finding that by the way