I have a 88 EA82 SPFI non turbo that bogs down at full throttle. I have no idea when it started. Up to 3/4 throttle it runs just fine. If I feather the throttle i can usually get it up to speed relatively quickly, but if I push it all the way, it loses all power. It also idles really high, even though the idle set screw is backed all the way out.

I've replaced plugs, wires, coil, filters, and even rebuilt the heads... what else could it be?

My best guess right now is maybe a throttle position sensor? any better ideas?

engine temp sensor, the one withthe green plug(88+) on the thermostat housing. This will tell the Idle Air Control valve to open or close(like a choke)

 

If the car is idling high, the car may think its still cold when its warmed up. Also try cleaning the IAC, located on the front of thethrottle body. You can soak it in Sea Foam. Try pinching off the hose and see if the idle changes.

... It also idles really high, even though the idle set screw is backed all the way out. ...

 

Could it be a Vacuum Leak Too? ... After Cleaning the Said Parts, if the Problem Persists, I Kindly Suggest you to Search for Vacuum Leaks.

 

Kind Regards.