my 85gs idles at 1300-1500 rpm when its warm. cold, well the choke is out when it's cold. it idled fine, then all of a sudden, it started doing this. so, when i put my foot under the gas pedal and pull up a little, it idles fine at like 800rpm. the moment you step on the gas, it will return to idle at 1500, sometimes if i am lucky 1200. does anyone know what causes this and how to fix? the car runs great however, no real misses and it accelerates fine. i know it must have something to do with the throttle return spring.

 

Sounds like your carb linkages are dirty and binding up. My car did the same thing and I just needed to clean the linkages. Try spraying the linkages down with carb cleaner then lube them up with WD-40. On my car, this took several sessions over a couple of days to get all the dirt cleaned out so be patient and keep at it. You should also check to be sure the throttle cable isn't too tight.

 

does anyone think perhaps that it could be something to do with the dashpot or the throttle return. the linkage sounds good. however, on the back of the carb, there id this round guy with a cylander shaped thing at its base. protruding from its base is a whie plastic lobe that comes in contact with part of the throttle, a meal ledge if you will. when the metal is pushed firmly against the white plastic, the engine idle returns to normal. i apologize for the hazy description.

 

:slapsforhead: Yup! The dashpot is defintely a top suspect! The dashpot is shock absorber type thing that slowly returns the butterflies to the idle position. It's purpose is the keep the engine from backfiring. It's also fully adjustable so yeah... check that out.

 

slap a new return spring on there