Idle Issue

[Can1991Ram]

My 1991 Fuel Injected Ram 50 seems to idle up and down when first started.. even warm. It sounds like it's "hunting" for an RPM much like when the idle screws are set wrong on a carburetor.

It eventually settles down but it quite annoying.

Maybe and idle speed motor issue?

[noahwins]

Has the ECU been remanufactured? Any vacuum leaks?

[Can1991Ram]

It's all original

[noahwins]

Pop open the ECU and check for any burn marks, bulging capacitors or goo on the circuit board. Take a whiff and see if it smells sharp and metallic. Then check each and every vacuum line for any dryness, cracks or brittleness using the diagram on the underhood label.

ECU is located under the passenger side kick panel. Look above the relay with a flashlight for 3 yellow plugs. It's hard to get out but it will come out if you jiggle it enough.