Re: Periodic Miss
 

Jack Dow wrote:
> At idle RPM's in gear '89 Wrangler 4.0 automatic tranny has a periodic miss
> or a studder step, however you want to describe it. Checked plugs, wires,
> distributor...what now? One other thing going on is each time I pull up to a
> light or stop for some reason the idle RPM's are different, while in gear
> naturally. Is there a connection with these to problems. Maybe the throttle
> position sensor?

Dirty idle air passage could do the RPM bit.
http://members.cox.net/wilsond/tb/tb.html

Also clean/check the connectors for your electrics.
TPS, CPS, MAP, etc

A miss is timing, you might have a plug/wire that's on its last legs.
Or you could have a failing CPS (Crankshaft Position Sensor) but usually
when that goes the engine simply stops.

First thing I'd do is clean the throttle body and give it a can of
injector cleaner.

(I'm basing this on the 93 4.0 which is different than the 89) YMMV

--
DougW