I recently had the timing belt changed for my 98 LS400. After I got the car back I noticed rough engin idling in the morning. The rough vibration goes away after the car is warmed up. But it never had this problem before. I took it back to the dealer and of course they said nothing was wrong. I felt like I was talking to a wall. Are there any additives or special engine oil I could use to get rid of this rough vibration when the engine is cold?

Thanks!!!

 

Check to make certain that they didn't disconnect the cold start fuel injector. You best hope that they didn't mess that belt install. If the cam gear moved a tooth then the timing might be off.