I had a similar problem, it ending being my tranny. It wasn't always
shifting right.

"Rogers" > wrote in message
...
> Hi,
>
> My 92 DOHC SL2 Saturn pulses noticeably at low speeds (higher also, but
> less obvious). It's like someone is playing with the gas pedal. I've
> changed the spark plug wires and plugs: no improvement. A mechanic also
> suggested I spray water on the coil packs to see if they are shorting: no
> change in engine idle during this test. There are no engine codes. I'm
> wondering if there is some kind of speed sensor that might be out of whack
> but not badly enough to trip a code. The engine seems to idle and run
> smoothly when the car is not moving. The problem is worse when the engine
> is warm.
>
> Any suggestions would be welcome.
>
> Roger
>