rough ideling on 82 datsun 720

i have a 1982 datsun/nissan pickup with a 2.2 liter engine and i cant get it to idle down below 1200 rpm and still run smooth. i took the carb apart and cleaned it but it wasnt stopped up so that didnt help. it acts like the carb is stopped up because i can choke nearly all the way and it runs smooth but still wont idle down. does anyone know what i can do to it to fix it.

im thinking the problem is more than likely a vacuum leak or a blown gasket

does anyone have any ideas whats wrong thanks

could be a bad intake gasket (manifold or carb) check in the normal way, with carbcleaner, brakeen, etc.

but it could also be a bad wax cylinder.

some of those motors' (z22) carbs had a wax cylinder that would hold the throttle slightly open to warm up the engine on a cold start. the wax would then warm up and pull off the fast idle.

look for a round cylinder on the side of the carb with a little rod sticking out of it (that may or may not be leaking blue stuff). it was not uncommon for these to fail and hold open the throttle a little and cause an un-tune-outable(?) fast idle.

this might be your problem, the kit to fix it is available through nissan.