the twinky don't have afm's

one of the common problems as they get older is the crank case breather valve under the exhaust manifold, or the pipe that links this to the inlet manifold around the back of the engine letting air into the system

it could also be a short in the tps, but you need to have the correct tps and then there's a specific way to refit and reset the base idle etc so it's not as simple as just undoing some screws