jerryparks

iTrader: (1)

I did maintenance on my LS400 '92 earlier this week ( changed plugs, cleaned the t body, and installed a new air cleaner. The maintenance resulted in a major increase in performance. The only problem that developed was a slight miss/ surge on the lst start up of the day. It lasts for approx. 1/4 mile and then goes away. Have I over looked something when I completed the TB process? I did not have any miss/ surge problem before I did the maintenance, although the performance was not nearly as pronounced as after the work was done. Any suggestions would be helpful! Thanks! ( BTW: I completed a very good cleaning of the TB.)

GS4_Fiend

iTrader: (22)

I would check if you got a vacuum leak and check the spark plugs. Does it do it all the time? Does it fall on its face when u step on the throttle then resumes normally?

jerryparks

iTrader: (1)

I dont see any vac leaks and I installed new platium NKG plugs as recommended on the how to site.
It just does it on start up. If I floor it, it just continues to sputter and surge. After a short drive, the cal levels out and the problem goes away for the rest of the day.

GS4_Fiend

iTrader: (22)

I would get the oxygen sensor readings checked out on a scope to determine this driveability problem. Or else it's just gonna be a guessing game.

fixmiester

May have washed something into one of the intake valve seats, or the valve stem seals, holding it slightly open, until things get warmed up. I've had sticking valves behave that way, but it's usually a wear issue. A compression test would show it, but a vacuum test would be quicker, just to see if the needle flickers at idle.

jerryparks

iTrader: (1)

I vac'ed out the plug holes good before I removed the plugs. The plugs were rather rusty, but there was no build up on them.