dahan

hi all, tonight while iwas cruising and i come to a complete stop for a traffic light the engine stop idling,so i start the engine again and the car drives normaly but the rpm showed 350 rpm in D position which is too low,and if i turn the a/c on the rpm jump to 1000 rpm,some times above and it wont go down untill icome to a complete stop for more than 10 second then it will go down to 800 rpm.so my problem is too low rpm while the car in complete stop ( D position ) and too high while the a/c is on even when i come to a compete stop(1000 >>>>>>1200 rpm) which effect the braking .{1995 ls 400,160000 miles}

tvd51

Check the throttle position sensor. Perhap, it's loose.
tvd51

dahan

thanks a lot tvd 51,but idont know where is it at.

tvd51

If you stand in front of your car looking at the engine you'll see a big black pipe on the left where the air gets into the intake (the silver part with Lexus logo on top of the engine), that big pipe is the throttle body, and attached to it in the front are two round things of about 2 inches in diameter, the one on the right is throttle position sensor (TPS), which has two little screws. Loose these screws and turn the TPS clockwise (I think) just a little bit. Tighten up these two screws and check the idle. Good luck.
tvd51