TBI High Idle and Dying since seafoam

[Stomis]

Well since I seafoamed my engine and changed the oil to synthetic it likes to die after idling for about 5mins. Usually it will idle at 900 the lowest and when it goes below that it sounds like its dogging down, although it may just be cause I'm not used to hearing it idle that low. I'll start by checking old cracked vac lines like your all going to tell me too but beyond that whats there to check.

When I first bought the truck it would idle like this and die. Then I put msd coil/cap/rotor on there and it stopped. I assumed it was because I wasnt burning all my fuel and it would eventually just build up. I think I need to rebuild my TBI to be honest. Thoughts?

 

[rolereversal]

Maybe after seafoaming it, it gummed up your spark plugs.

 

[Stomis]

Hmmm I never thought of that. What do you guys think?

 

[dyeager535]

Pull them and look.

IIRC 900RPM is way high for TBI idle, I believe spec is something like 550.

 

[Mike D]

Carefully spray some carb cleaner at the base of the throttle body and check the throttle shaft for wear. You may have a vacuum leak at the base of the throttle body ( cheap thin factory gasket ) or the throttle shaft.
Either of these conditions agravate engine idle.

 

[Stomis]

Yeah I'll try that at work tonight and see if it makes a difference. I'm gonna rebuild the tbi anyway.

Btw thats like major gas mileage loss with a bad TB gasket or a vacuum leak isnt it?