Odd stuttering

99 XJ, aw4, 4.0

Whenever I start my jeep when until it hits around 210, I get a very odd stutter when I take off from a stop. Basically, I get on the gas and the RPM's just drop below idle then go up. Really really weird and was wondering if anyone knew what this was.

Gotta start with the basics.

When was the last time that your tuned your '99 up?

That consists of fresh gapped spark plugs, plug wires, distributor cap and rotor. A bottle of quality fuel injector cleaner (BG44K or Techron) is also helpful once in a while in optimizing fuel injector spray pattern.

It has probably been quite some time... I figured the dealer did it before I bought the jeep but that is coming up on 2.5 years ago.

Anything else I should address while i'm at it?

Is your check engine light coming on at all? I have an old Celica that exhibited the same symptoms you described and it ended up being a crack in the rubber intake boot that only presented itself on take-off as the engine moved slightly and the crack in the boot presented itself.

I see you're in Reno.....pretty dry climate. You might take a look and see if the boot has deteriorated at all.

That sounds like a lazy O2 sensor to me. I had one that would not set a code but caused stutter very much like that. Unless you have one lying around, I would not replace it without capturing the real time data though. No point in throwing money at a possibilty.