sohc start up issue

[okinawa drift]

I have a 90 240sx with a ka24e, and it is freshly rebuilt, about 5k on motor, it runs really solid, got it up to 120 no problem

but anyways

sometimes when i drive to the store or something a couple miles away, and the engine is all warmed up, i got inside to get something then come back out to start my car again, the car will jump from 1500 - 2000 rpms about.. 4-5times, then stop and keep a constant idle at 800... this never happend when i got to start the car in the morning, only happends sometimes after the car is warmed up..

anyone have any idea?

[SirSilvia]

dirty MAF? i got no clue

[Dattebayo]

Intermittent sensor wiring somewhere probably. Jiggle some of the wires in your engine bay until you get the same results...

Maybe the wax in your idle sensor is gone and the thing needs to be replaced.