My 94 gts st204 5sfe has some issues when idling. I sense it is supposed to idle at 1100-1200 rpm, and not dip below that. It struggles sometimes, and goes between 400-800rpm. Help?


I already changed:

Spark plugs
Distributor cap
Distributor cables connecting to the spark plugs.

Thanks!

Ideally, idle is at 800 +/- 50 rpm.

looks like you got the typical items of concern replaced. next i'd check/replace the fuel filter, fuel pump, and ignition coil.

When I first made the changes, it sat around 1100. Also, when it occasionally stops choking it jumps and sits back at 1100 too.

>


Can I diagnose these without replacing them? Thanks

>

i have similar problem.... i have leak from the manifold...si check the manifold or manifold gasket

good luck

Have you pulled out the IACV and cleaned it? Its very prone to carbon build up and makes the car idle like crap when it does so.
Basically pull off the throttle body and its underneath (assuming you have a 5sfe, not sure about 7afe). There's 4 brass screws holding it on which will be near impossible to get off without stripping so try use an impact screwdriver to get them off. Then use almost a full spray can of throttle body cleaner to get every last bit of carbon out and of course clean the TB since you have it out. Replace the gasket on the IACV and put it all back together.