throttle body change

Changing something like the throttle body on engines that don't have mass air metering (you should have a speed density system) can cause problems like you list. You might need to have a chip burned to compensate for the change in airflow through the larger throttle body.

As a side note, unless you have done other modifications to increase airflow after the throttle body you won't see much of a benefit from it. Especially if you are still using the stock heads and cam. You probably are or you would have even worse engine problems. If you plan to keep modding the engine you should just switch it over to a mass air system and be done with it. It will save you a lot of headaches down the road.

Ehh, I don't think you can do that on an 86