- This topic has 51 replies, 9 voices, and was last updated 12 years, 10 months ago by
.
-
Topic
-
-
Replies
-
At first glance, I too was thinking TPS, but I am willing to bet that you have an auto trans and the problem could possibly be there. When your RPM picks up, and I’m assuming that the engine revs accordingly, does the car feel like it is slowing or just not accelerating with the RPM gain????
Quoted From Pacco46:
At first glance, I too was thinking TPS, but I am willing to bet that you have an auto trans and the problem could possibly be there. When your RPM picks up, and I’m assuming that the engine revs accordingly, does the car feel like it is slowing or just not accelerating with the RPM gain????
Welcome to the forums!
If you read the entire thread all your questions will be answered.
I don’t think its a transmission issue as the vehicle accelerates fine.
Quoted From college man:
I just went to grand prix forum. according to other people with your symptoms they disconnected the battery to reset the computer and the problem went away.
you say you have the engine or trans tuned? try the reset or return the tune to stock and see if problem goes away. also I don’t know about having the egr
disconnected.does’t sound good.I’m actually a member over there. Ill try to reset the battery again and see what happens. I have the PCM (powertrain control module) tuned by a tuner who specializes in tuning 3800 series engines.
And I have the egr disconnected because all it is for is emmisions and I don’t want exhaust gas to be cycled back through the intake manifold.
So, I unplugged the battery and put the stock PCM back in. The car is still doing it. Im running out of ideas, I checked the TCC fuse to see if it was out, but its good. I plugged the EGR back in, no change. Any other suggestions?
Quoted From Cameron92:
I’m actually a member over there. Ill try to reset the battery again and see what happens. I have the PCM (powertrain control module) tuned by a tuner who specializes in tuning 3800 series engines.
And I have the egr disconnected because all it is for is emmisions and I don’t want exhaust gas to be cycled back through the intake manifold.
Actually, EGR is also used to cool combustion temperatures to no only reduce NOx (emissions), but also prevent pinging, or pre-detonation. Just saying it’s not ONLY emissions related.
Quoted From Beefy:
Actually, EGR is also used to cool combustion temperatures to no only reduce NOx (emissions), but also prevent pinging, or pre-detonation. Just saying it’s not ONLY emissions related.
Oh, ok, I was misinformed then, thats what I was told. I have it plugged back in now anyway.
After reading through this thread I would guess it has something to do with a slipping transmission more than anything as I can’t really think of much else that would cause an rpm fluctuation like that as you cruse. You might try resetting it as suggested as that is an easy thing to try but if the problem still exists I might turn my search to the transmission. If memory serves that is a difficult transmission to check the fluid in as I don’t think it has a dipstick which means you have to jack up all 4 wheels so that it is level and remove the inspection plug as the engine is running to check the fluid level.
Quoted From EricTheCarGuy:
After reading through this thread I would guess it has something to do with a slipping transmission more than anything as I can’t really think of much else that would cause an rpm fluctuation like that as you cruse. You might try resetting it as suggested as that is an easy thing to try but if the problem still exists I might turn my search to the transmission. If memory serves that is a difficult transmission to check the fluid in as I don’t think it has a dipstick which means you have to jack up all 4 wheels so that it is level and remove the inspection plug as the engine is running to check the fluid level.
The dipstick is actually pretty easily accessible, the fluid is at the proper level and its kind of a pinkish red. I think I’m going to go back to ignition (faulty coil pack maybe?idk), Im completely lost.
If you decide to go that route, you have to make sure you stress test your coils under a load.
Did you ever look at the IACV?
Also, i would look for any TSB’s on your issue also.
I would have those codes checked as they may have some information that my correlate to the fluctuating RPM’s.
I believe most Autozone’s can scan domestic ABS codes now.
When the RPM’s begin to fluctuate, if you gently depress the accelerator pedal, does the vehicle pickup and coast in that problem RPM range if that makes sense?
Quoted From dreamer2355:
I would have those codes checked as they may have some information that my correlate to the fluctuating RPM’s.
I believe most Autozone’s can scan domestic ABS codes now.
When the RPM’s begin to fluctuate, if you gently depress the accelerator pedal, does the vehicle pickup and coast in that problem RPM range if that makes sense?
I get what you mean, and I’m not to sure, i lightly press the throttle at the end of the video if that answers your question.
Did you check your idle air control valve? mine was doing something similar because the valve went bad and the wiring was frayed. the valve has four wires running to it on your throttle body and are paired for what direction the valve moves in. they should both be getting system voltage
Got a video of what is happening, it turns out that brake input has no effect on the problem.
- You must be logged in to reply to this topic.