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Rock On 07-23-2013 09:57 AM

Not shifting under heavy acceleration.
I have a 02 Jeep GC Limited 4.7L and when I accelerate( in any gear AT) it won't shift and won't go over 3000 rpm's . If I drive normal it shifts and drives fine , only under heavy acceleration or hill climbing it boggs down and won't shift. Any ideas will help. Also I've replaced the TPS , Cam , Crank , O2 sensors , both converters w/ exhaust . Also tuned it up w/ plugs and wires. Help??

2005JGC 07-23-2013 02:23 PM

Re: Not shifting under heavy acceleration.
It really sounds like a restriction of air flow... plugged exhaust, plugged intake... its likely not shifting simply because the rpms compared to throttle command (TPS input to PCM) is saying we are not as high as we want to be for a full/high throttle shift. There is less air flow with lighter throttle so a restriction wont affect it as much.

I don't know how you replaced plug wires because there are none on a 4.7l V8

Lastly was this a problem BEFORE you replaced all of those parts? If it is something that has developed since you replaced them its REALLY hard to say... Chrysler products are very picky about the sensors they use and if you threw a bunch of crappy Chinese parts on it, the problem could be any one of the things you just replaced.

Rock On 07-23-2013 02:38 PM

Re: Not shifting under heavy acceleration.
Well the Jeep has a new exhaust and I have also taken the air box off thinking the same thing (air restriction) , but the same results. Also yes this was the problem before all the parts I've replaced . And as far as the wires I meant the coil boots sorry.

2005JGC 07-23-2013 04:27 PM

Re: Not shifting under heavy acceleration.
How much of the exhaust was replaced?

if a catalytic converter came apart and rattled downstream it may be plugged at the muffler inlet.

Frango100 07-23-2013 07:33 PM

Re: Not shifting under heavy acceleration.
Did you check for any fault code set? (ignition switch off/on three times and leave in on at the third time. Odometer will show DONE when all ok, or a fault code)

Rock On 07-24-2013 06:57 AM

Re: Not shifting under heavy acceleration.
The exhaust from the headers back has been replaced , both converters and the muffler. and yes I have a snap-on scanner and it had several misfire codes and two transmission line pressure codes. I had the tranny serviced at my transmission shop and they hooked it up to their tranny scanner and the shift sensors were fine and the TCM was fine.They then cleared the codes. No codes since then and no misfire codes either, but still not shifting under heavy throttle. The DTC codes were PO300, PO302, PO303, PO304, PO307, PO1C9 Line pressure low fault, and PO1C8 also line pressure fault. Of course the PO3 are the cylinder misfire codes. Any more ideas will help keep them coming.:confused:

Frango100 07-24-2013 06:31 PM

Re: Not shifting under heavy acceleration.
I have never seen those P01C8 and P01C9. Are you sure it wasn´t P0108 and P0109? Both are MAP sensor faults and could have to do with not enough power to accelerate.

Rock On 07-24-2013 07:13 PM

Re: Not shifting under heavy acceleration.
Sorry PO867 and PO868 are the generic codes my scanner says both.

DHart 07-28-2013 04:11 AM

Re: Not shifting under heavy acceleration.
I would do as Frango suggested and do the key dance, I dont know about other Jeeps, but this model really dosn't play well with generic scanners.

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