RPM shooting up on J

[alex61089]

Ok so when im driving and i put my foot on the gas when i get to about 20mph the rpm shoots all the way up to 3 really fast then drops. Then the car is fine until i get to about 50mph and the RPM reaches 3 and stays there then jumps up to 4 then drops down. Now i was told maybe a screen? or maybe it's one of the sensors? i checked the trans fluid and it is good so im not sure what to think.

[NASCARLANCE]

Does the trans quit pulling when it revs or does it fill like the trans is pulling the whole time?Is it every time or is it intermittent?

[alex61089]

well when i put it in drive it creeps forward but when i get to about 20mph it feels like the trans is pulling. I'm guessing that by saying pulling you mean it's trying to keep the moving forward? I feel a pull when it revs then the RPM drops and so does the pulling. once i get up to about 50mph it does the same thing but it will go back and forth. Now i think it's the fluids because im pretty sure it hasent been changed in a while and when i first started driving the car it didnt do this.

edit: I checked the trans fluid again and it looks like a brownish color. and it happens here and there but it is becoming more frequent =/

[J30inthe sun]

...a brownish color. and it happens here and there but it is becoming more frequent =/

Sound like the transmission is on its way out.

[driverdriver]

Check your ECU to see if your getting a transmission code?

If not your transmission may be on its way out.

Transmission self diagonostic procedure is in this thread:

zer...age=2

[alex61089]

Im sorry i kind of mis represented exactly what the car is doing. When im getting to about 60mph the throttle is jumping that is im going up to 5 rpm i believe and when i let go of the gas im dropping to 4 rpm and when i give it gas it jumps back up to 5 let go of gas again drops to 4. Now i was in the car with a transmission mechanic and he said its odd because he has never seen something like this before. He thinks it might be my TPS. i just tried to do the self diagnostic test and it will not work. my AT light does not blink at all so im lost.

[GerryO]

That's a pretty big swing in engine rpms.

What's the engine idle rpm with the engine fully warmed up, the transmission in D and sitting fully stopped with your foot on the brake pedal?

Check/set the TPS output voltage to between 0.40 to 0.45 VDC.

Clean the MAF too.

Check all related under the hood connectors, also applying some dielectric grease to the female ends of the individual contacts (don't use dielectric grease on O2 sensor related connectors).

[alex61089]

The RPM sits around below 1 when idle just before the one mark it maintains there while in the drive shift and when stopped. They are going to drop the pan tomorrow for me to see if theres any junk in there; if not... then it could be the transmission or one of the sensors.

[alex61089]

I took it to a transmission mechanic today and they dropped the pan. There was really nothing in the pan. Just a little bit of gunk and the oil wasent bad either. My mechanic is not convinced that it is the transmission; plus they ran a diagnostic on it and no codes came up for a problem with the transmission. That does not eliminate that there could be a problem though he said. So we think it might be the TPS so im gonna try that and if it isnt that I'm guessing the transmission is bad or something else? Your advice would be greatly appreciated

edit: by the way they changed the fluid and it seems to shift better.

[kbflip02]

I took it to a transmission mechanic today and they dropped the pan. There was really nothing in the pan. Just a little bit of gunk and the oil wasent bad either. My mechanic is not convinced that it is the transmission; plus they ran a diagnostic on it and no codes came up for a problem with the transmission. That does not eliminate that there could be a problem though he said. So we think it might be the TPS so im gonna try that and if it isnt that I'm guessing the transmission is bad or something else? Your advice would be greatly appreciated

edit: by the way they changed the fluid and it seems to shift better.

check your ECU for codes first...then go from there...

[alex61089]

how do you check your ECU for codes?

[kbflip02]

zerothread/217489-that is how to check your codes...

[kermank]

Hello alex,I have the same problem with my j30,if you have fixed the problem by now,I would appreciate you to give me clue on what to do to get my car work. Thank you!

[GerryO]

Try checking the TPS (throttle position sensor) output voltage at idle and its' functions (or just replace with an OEM new one and adjust it) and for a KS (knock sensor) code (which doesn't trigger a CEL light).