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1986 C4 Coupe L98-----
So I've been working on getting my car running and I've replaced so many parts that I'm running out of options. It runs at an incredibly low idle (almost stalling) as if it isn't getting enough air. If you rev it and let off the gas quickly it completely stalls out and if you give it too much gas from an idle it stalls as well.
32k original miles
Here's what I've changed:
Tps
Iac valve
MAF sensor
Every relay on the car
Distributor Cap
Rotor
Full Intake Gaskets
Plug Wires
Spark Plugs
Valve Cover Gaskets
Fuel pump
Fuel filter
Computer
Oil change
High Grade Gas
Injector treatment
Injectors
NewRockies Security Bypass Module
Belt
it looks like you touched base on everything but you did not indicate you cleaned the throttle body. pull the thing off, remove the IAC, TPS, and give it a good cleaning. get a couple cans of carb cleaner and spray the hell out of the thing. get it squeaky clean -- that just might solve your problem. I'd also check for vacuum leaks. keep us posted!
I have an 89, my car had very similar symptoms car would idle low but mine would stall and I would have to keep revving the engine and use carb cleaner on the IAC and eventually it would idle. I cleaned the TB and swapped the IAC car ran good for 2 weeks then the problem would come back. Ended up replacing the ECM, that was close to 2 years ago and haven't had a idle problem since. a $65 part caused so much head aches.
Is the Coolant Temperature Sensor reporting accurately?
Have you checked for vacuum leaks?
I replaced the coolant temp sensor about a week ago, sorry I didn't mention it. I've changed so much that I forget unless someone mentiones it. It is reporting accurately. I'm going to check for any vacuum leaks today and will report back later this afternoon. Thanks!
it looks like you touched base on everything but you did not indicate you cleaned the throttle body. pull the thing off, remove the IAC, TPS, and give it a good cleaning. get a couple cans of carb cleaner and spray the hell out of the thing. get it squeaky clean -- that just might solve your problem. I'd also check for vacuum leaks. keep us posted!
I did clean the throttle body (cleaned the main butterfly valves with TB cleaner) but I'll pull it off and try to clean it better if I can. Thanks!
OK, so. the car wouldn't even start. it was just dumping fuel into the engine. I unplugged the TPS and it started up perfect. While it was running i plugged the TPS back in and it continued to run pretty good. I let the car warm up to operation temp and shut it down. I went to start it again and it wouldn't start again. So I unplugged the TPS again and it started up beautiful. The TPS is brand new and its my 3rd one so far. Should i get another one again? Do I absolutely need the TPS connected? It runs perfect without it plugged in.
Rough Idle
