Hi all. My Girlfriends car has a real high idle. Its a 94 SL1 SOHC TBI
automatic car. The idle adjustment screw(or where it normally is has
threads sticking out one side to stop the accelerator cable attachement
wheel but on the side where the head should be there is what looks like
a freeze plug in the hole. How do I lower the idle on the car?

 

There's either a vacuum leak from a break in a vacuum line or (don't know if there is one) the idle air control valve is sticking. Cleaning the throttle body and linkages with carb cleaner solvent may free up any deposits to allow proper closing of the throttle plate and IACV. The hidden idle adjustment isn't to beadjusted unless you're familiar with the factoryprocedure setting up the throttle body with plugging the IACV port.

 

Most likely a intake gasket leaking spray brake clean or water where the Intake manifold bolts to the block. If the engine hesitates or dies u got a leak.

 

" Cleaning the throttle body and linkages with carb cleaner solvent may free up any deposits to allow proper closing of the throttle plate and IACV."

I agree with this reply. Could also be a cracked PCV valve hose. I'd look at these items first they are very commonEdited by: sw2cam