i have a 92 rs, 305. and got a new sensor and throttle body gasket replaced and now when i start the car it goes up to 1000 rpms then quickly drops to 600-800 and it goes slightly up and down randomly while in park. and when im driving sometimes it feels like the car is hesitating to accelerate then it kicks in.any advice as to whats wrong cus im afraid that when winter comes the car will just stop running when its cold

It may be the throttle body gasket not sealing correctly. remove it and research the interface between the body and manifold.

You might want to get a spray can of fuel system injector cleaner and clean the manifold of debris. All the nooks and crannies.

If the car ran fine before the changeout, does not work correctly after, then it might be the gasket.

Welcome to the Club! From where in Mass.?

thanks for the tips. my dad basically said the same thing, he knows a lot about cars he restored his 72 mustang and fixed my sisters car (an 82 firebird) plenty of times so this shouldnt be a problem. just wanted to get someone elses opinion so i can really know wats wrong before i do anything. oh and im from peabody.