94 4.3 TBI high idle

[perplexed783836]

So I took MT's advice got a timing gun and checked the base timing which was way out even though the mechanic said it was timed dead on. Guess he dosn't know how to disconnect the wire to the computer. Anyhow this cleared up my engine knock. I now have an issue with the truck sitting at a high idle around 2000 RPM especially when it's warm out. The check engine light comes on but I have scanned for codes numerous times and none are present. Sometimes if I turn the truck off for 10-15 sec and restart it runs normally and no check engine light. Has anyone had this issue or any thoughts on the matter would be appreciated.

[MT-2500]

Originally Posted by perplexed783836

So I took MT's advice got a timing gun and checked the base timing which was way out even though the mechanic said it was timed dead on. Guess he dosn't know how to disconnect the wire to the computer. Anyhow this cleared up my engine knock. I now have an issue with the truck sitting at a high idle around 2000 RPM especially when it's warm out. The check engine light comes on but I have scanned for codes numerous times and none are present. Sometimes if I turn the truck off for 10-15 sec and restart it runs normally and no check engine light. Has anyone had this issue or any thoughts on the matter would be appreciated.

High idle is caused by a vacuum leak or IAC/TBI not closing.
First thing.
Check and or replace the base gasket on the TBI.
Check the IAC valve.
Also check for any vacuum leaks at pcv valve and vacuum lines and brake booster.
LET US KNOW WHAT YOU FIND

[perplexed783836]

Sorry for the delay in replying, It was the gasket on the TBI all works great now. Thanks

[MT-2500]

Originally Posted by perplexed783836

Sorry for the delay in replying, It was the gasket on the TBI all works great now. Thanks

No problem.

You are welcome and thanks for posting back the fix.
Good luck