HELP 98 Cherokee "miss"

When driving at road speed (35-60), particularly when the engine is not warmed up, I recently developed a "miss", a stutter or hesitation, when applying the gas. I thought it was an engine miss at first and replaced plugs, rotor, cap, etc. Engine runs fine. Now I think the "miss" may be in the transmission. If I'm driving and give it a bit of gas it feels like the engine is miss firing, but I think it is the transmission skipping. If I punch it down enough to drop to a lower gear, the stutter stops and engine sounds fine. Once everything warms up, everyhting seems to run well.

So, could it be a punch-down switch on the tranny or something in the transmission that is acting up? Anyone else ever have this occur? Of course, I hope it is something simple, not a major transmission problem.

Mike

Reply to
mbyoh
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Engine RPM related. That can be any number of things.

The problem in the 98 is they got rid of the abiltiy to pull codes with the key on-off-on-off-on trick. It takes a diagnostic tool.

Here is a laundry list.

Bad or failing coil -can cause miss particurally at higher rpm

Bad connectors to the CPS (crankshaft position sensor) -usually when hot, but when the CPS fails your jeep stops running

Bad O2 sensor - Shows up as bad MPG and decrease in power as the engine runs too rich - will also show up as excess carbon on the plugs

Dirty IAP (idle air passage) - rough idle usually is the first indication

Clogged fuel filter - usually shows up as lack of higher rpm power but can cause lean pinging at full throttle.

Since you already did most of the ignition, I'd suggest start by cleaning the connectors (watch you don't get contact cleaner on the paint and use a good dilectric grease to keep the water out.

And clean the idle air passage.

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The other thing to do is reset the Jeeps brain. Just pull the battery for 10-15 min. Amazing what that can clear up sometimes.

Reply to
DougW

Dirty TCC connector or TCC starting to go. I fix 42re's on Heeps all the time.

Reply to
Cheeky Bastard

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