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Jeep Cherokee XJ, 1997, RPM surges when accelerating?

Maintenance/Repairs
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#1

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

#2

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

#3

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

#4

First.

Is the Check Engine light on?

Tester

#5

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.

#6

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

Tester

#7

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.

#8

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

#9

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

#10

YEP!

Tester

#11

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.