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Jeep Cherokee XJ, 1997, RPM surges when accelerating?

Hey everyone,

I have a '97 Jeep Cherokee Sport, around 187,000 miles on the odometer. Once a month or so, I will have a day where when I accelerate, the RPM’s will surge up and down, but it will feel like it is coasting, as if I do not have my foot on the pedal. There is also an audible “rattling” sound, much like a rattlesnake rattle, right under the steering wheel it seems. It will happen for about five or six seconds, and it will then go back to normal for another month.

  • Side note, (This has only happened twice), I had a moment the other day where I could not accelerate for a few seconds, until an audible “popping” sound was heard on the right side of my engine, and then everything went back to normal. RPMs stayed around 2-2500 during that time.

Some have said it could be the throttle position sensor? I also think it could have something to do with my transmission, because I checked my dipstick and it is a reddish-brown color. It is very light brown and you can still make out the red, so I just assume this is just used but it is still functioning normally. No metal chips or anything.

Thank you all!
-Marshal Radulov

Have the transmission fluid serviced including removing the pan.

If there’s metal chips, it won’t be on the dipstick but in the tranny pan.

Tester

Would that cause the acceleration surges when and only when accelerating? also would that mean my transmission is toast & I need a rebuild?

First.

Is the Check Engine light on?

Tester

Not for anything related to that. Once, it had a check engine light for a day and went off, about a month ago. I looked up code, it said “NO BUS”, some wiring connection for my computer or something. Surely that isn’t related to this problem? It hasn’t been on since.

Then have the transmission fluid serviced, just because of the color you describe.

Tester

Definitely “Red/Light Brown Semi-Translucent”.
Do you recommend just replacing gasket and fluid or doing a whole pump thing where they take all the fluid out? I could do the gasket replacement & refill myself.

A pan drop only removes 30-40% of the total amount of transmission fluid that the tranny holds. The rest stays in the valve body, torque converter, and the tranny cooler/lines.

So it would be the same as only changing half your engine oil.

If you want, you could just do a pan drop to change the fluid just to see if there’s any metal in the pan. And if none is found, take it to a shop and have all the tranny fluid replaced.

Tester

Sounds good. In the event that there IS metal in the pan, that would mean game over for my transmission right?

YEP!

Tester

Concur, it does sound like an automatic transmission problem. Good advice above.

I’ve had rattling sounds like that happen b/c of a bad electrical connection which caused a relay to turn on and off rapidly. In my case it was a relay related to the EGR function. The “Bus” diagnostic code might be related to that. But I doubt it is the cause of the surging rpm symptom.