I have a 1990 ls 400 and my idle is running very high.
I have no vacume leaks and have no engine codes.
I have changed both tps's and am beside myself with this problem. Can anyone lend a hand please.

 

welcome, visit www.lexls.com and look at how to adjust your idle with your TPS.

 

This happened to me a few times. It maybe that your idle air control valve got stuck in wide open position. This happens when the bearing inside of it locks up in wide open position.
Have someone shut off the engine while you listen or touch the IACV. I should click when the engine shuts off. If it doesn't that is your problem.
If not:
check ur throttle cables to see if they are too tight. Maybe ur floor mats are pushing the peddle a little bit.

 

yhanks for the insight. I have not checked the IAC and I am on my way out to do so this minute> Thank you again.

 

Your great. Thank you. I will check out the IAC

 

Glad to help. I hope your problem is just something simple and cheap.

 

usually an iac will make ur idle eratic, also ur tps can be checked with a feeler gauge and an ohm meter,also a new one is to be set the same way