'91 civic lx 1.5 d15b2 dpfi auto tranny.
I cleaned the inside of the throttle body spotless. Lubricated throttle cable and the other cable hooked up to tranny. Cleaned and lubricated pedal assembly. Throttle cable has 10 - 12 mm of slack as recommended. I did the idle adjust procedure. No vacuum leaks.

Coming to a red light I'm stopped on the brakes and idle is at 1k, I pull up the throttle pedal and idle drops to 800.

In park, if I blip the gas pedal, idle hovers between 1200 and 1000. I pull up on the gas pedal and it drops back down to 800 perfect.

Throttle cable disconnected, opening the throttle by hand and letting it close will leave about 1mm open resulting in high idle until I move it closed all the way. I cleaned and lubricated the throttle mechanism and springs.. still the same.

This is driving me crazy. I'm worried my gas mileage is down because the throttle wont close completely unless I pull up on the gas pedal or push the linkage closed by hand that last bit. Any insight? Thanks

 

Are you sure you're looking at the throttle plate and not the tandem air valve? On a DPFI, the throttle plate is below the tandem air valve.

If it is indeed your throttle plate not fully closing, it could likely be that the diaphragm is blown out in this dashpot which holds the throttle open slightly before the engine is running. Try removing the dashpot and capping the vacuum line to see if that helps.