Losiho

Recently my 1995 LS400 has a very rough idle. This only happens when the transmission is in Drive with the a/c off. The revs are barely above zero, and the tacho needle shakes, along with the steering wheel. Otherwise, the are no other problems. It idles fine in Park or Neutral, and with the a/c on, and drive well once on the move.

Has anyone got any suggestions ? Would resetting the ECU help at all ?

GA400

Resetting the ECU wouldn't hurt.
A fairly common problem on the LS400 and the GS400 is the throttle position sensor. Search results here https://www.clublexus.com/forums/sea...der=descending

Of course there are the other usual suspects of worn/fouled spark plugs, spark plug wires, dirty air filter, fuel injector issues, etc.

Good Luck and let us know what you find out.

Losiho

Thanks for the advice and the link GA400, unfortunately resetting the ECU didn't help. Hopefully it'll be diagnosed at service.