Hello all,
Well it's happened to me, the dreaded surging idle and stalling engine that often occurs with our early gen Ls400's. I have searched but nothing's actually pointed me in the right direction with my problem.
Here are the symptoms. My 1990 LS400 drops to very low RPMs after a few minutes of driving. It will sometimes drop low then surge up to about 2000rpm or flat out stalls.
However, this does NOT occur after a long drive or anything, it will happen after 2 mins of driving. Even when I am driving around 40MPH, the car will slow down then start surging or stalls. No matter how much throttle I add, the car will drop RPM's (200-300RPM) then surge upwards or just flat out stalls. It will not allow me to drive.
I have spent 2 days searching on this common problem without results, as everyone else's seem a bit different. Such as the 94-95 with the ECM problem or 1st gen's like emyself doing a TB cleaning and MAF cleaning which solves the problem.
I've taken a look at my MAF and it looks clean. I'm not sure what to clean on the TB but I do not think that is the problem. I do not think it is the idle control valve because my problem will occur even when im on the freeway doing 60.
I want to say it is a bad MAF, but I don't want to go out and buy one without a second opinion. Could someone point me in the right direction? Any input would be greatly appreciated!
Thank you.