they <ford dealer> tuned it up before I bought it, i was checking the
plugs & air filter & found they were new. i shot some carb cleaner
through the intake- did not help.

The plug wires look new, but how do you check them with an ohmmeter?

I'll pull the dist cap & look for obvious <crack> , i thought you could
not set the timing on these.

sounds like many possibilities.... after the timing light check i'll
head to advance & get a Haynes.

Thanks for the help!

Stephen Cowell wrote:

> "Robert Coffey" > wrote in message
> news:ghEme.9935$3u3.9116@trnddc07...
>
>>I just bought my first jeep! a 98 4.0 tj. when the engine warms up it
>>"hiccups" at idle or when running at low rpm not under load. 81k miles,
>>new air filter, spark plugs, plug wires look good. any suggestions?
>>
>
>
> Did it do this before the tune-up? We need to know whether
> something in the tune-up did this, or not.
>
> Might be time for an O2 sensor (or two...).
>
> Have you checked the plug wires with an
> ohmmeter? How's the cap and rotor?
> Vacuum advance working? Timing set?
> No vacuum leaks?
>
> You can use a timing light on each plug
> wire to see whether the 'hiccup' coincides
> with a certain cylinder spark drop...
> three things, fuel, air, spark... one is
> missing, could be fuel (sticky injector)
> or spark (bad plug (it's happened!) or
> cable, rotor, cap). Normally you'd feel
> a bad position (crank,cam) sensor under
> load as well as no load... you can check
> your TPS (throttle position sensor) easily...
> get yourself a Haynes, Chilton or (best!)
> factory manual. Good luck.
> __
> Steve
> .
>
>