Engine surge (intermittent) at start

[Sprint45]

Hi guys,

I've read past posts about rpm surge and IMG's. But i have a question? ON OCCASSION and not all the time at start the engine will increase RPM's slightly about 3 or 4 times then stay at idle and run fine. IT does not happen all the time and not at a reqular interval.

To me if it was the IMG it would happen all the time wouldn't it? if the leak is there it won't magically appear and disappear. Are there and other possiblities i.e a sensor that could also cause this?

Thanks
Mike

P.s Amigo will be in your neck of the woods for Xmas (rochester) thanks in advance all....

[rodeo02]

1998 trooper? Yes the IMG can be intermittant, sporatic. 2) The idle air control valves (IAC) on the 1998 & 1999 can cause this. 3) Idle up pressure switch on the power steering pump can also be a culpret. 4) Check the rubber boot where the throttle cable meets the throttle linkage. The boots can get soft, disintegrate and stick. A very tiny bit of silicone grease will fix that- just dont use alot as silicone will kill oxygen sensors if it gets into the combustion chamber.

G/luck
Joel