Hey everyone. Name's Kevin and i'm new here. I just got a 93 ls400 w/180k and everything was good until I got my engine cleaned. I'm guessing it's an electrical problem. I have been searching a way to fix my idle problem but haven't found something similiar to my problem. Basically when I start my car and i'm on park, the idle goes up and down & up and down...from 1500 rpm to 2000 rpm as if i'm pressing and depressing the gas, but when I put the car on drive or reverse it stays put on 1300 rpm which is still high. This is an ON and OFF issue for me. So sometimes the idle acts up like that and sometimes the idle is where it's used to be at 500-600rpm and I figured it has something to do with the electrical also because the radio sometimes doesnt work and sometimes it does and also the speedometer acts up too. I'm guessing water got some sensors wet or somethings wrong with the idle control valve. If someone could give me info on how to fix this idle problem, that would be great. Thanks!


here are some pics.

 

Have you tried resetting the ecu? (remove batt neg term for 10 minutes).

If that doesnt work, i'd try maybe blasting the whole engine bay out with compressed air. There could be water still in a sensor connector or spark lead maybe, high pressure air in all the connectors/plugs you can get to could help. I assume you've had the car nice and hot for at least half hours or so since the problem showed up? If so, i guess it should've dried out

 

Most likely got the MAF wet. Can try to dry it out throughly, but will take some time to do.

 

car looks sweet! but i also think it may be the MAF, be careful when drying it, u dont wanna damage the wire then pay money for a new one .