I have a 1992 fleetwood the engine was replace with a used engine. When i start it cold it idles just fine. once the engine warms up the engine idle goes up and down. the idle speed controler goes in and out sometimes to keep the engine running..what is the problem?
hard to pinpoint your problem without more info. could be the oxygen sensor (only read by the computer when warm), could be a failing closed throttle switch in the isc, could be a bad ground. check the engine block grounds first. make sure your 02 sensor toggles between rich and lean.