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Cant figure it out

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Old 09-01-2011, 08:38 PM
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alright, so i just started college last week and i occasionally have to drive 30 miles to get there, i just did my head gasket over the past week to make sure i didnt damage the cylinder head. before i did the head gasket my jeep was doing something weird. it would be going down the hwy just fine and then all of the sudden it will kinda start to buck, the RPM drop anywhere from 250-500 RPM, and it really jerks. it only does it when im on the gas even when i maintain speed. i have changed the TPS, CKP sensor, and even the PCM and it still does it. im all out of ideas and i cant figure it out. HELP!!!
Old 09-01-2011, 09:57 PM
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it might be a fuel issue... i've had that happen to my 93 p/u... but it was the wires/plugs/cap and it ran fine after that.
Old 09-01-2011, 10:19 PM
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already did the cap, rotor, wires and plugs
Old 09-02-2011, 02:45 PM
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wow nobody else?
Old 09-02-2011, 03:17 PM
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Try checking the fuel pressure at the rail.
Old 09-02-2011, 03:19 PM
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i did that when it first started doing this, it has at like 40 or so (cant remember it was 5 months ago
Old 09-02-2011, 03:31 PM
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even if theres no check engine light codes should be checked
Old 09-02-2011, 08:19 PM
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Fuel filter dirty.

Fuel pump "sock" dirty.

Fuel pump inadequate pumping under load.
Old 09-02-2011, 11:25 PM
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fuel pump, tank, lines and filter all got replaced (at the same time) to be able to get it running back in December and i only run gas that has no ethanol. and OBD I doesnt store codes
Old 09-03-2011, 12:11 AM
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Originally Posted by Jeepjunky
fuel pump, tank, lines and filter all got replaced (at the same time) to be able to get it running back in December and i only run gas that has no ethanol. and OBD I doesnt store codes
Obd1 does store codes. Think your cat might be plugged?

Last edited by Slick761; 09-03-2011 at 12:21 AM.
Old 09-03-2011, 12:18 AM
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Originally Posted by Jeepjunky
fuel pump, tank, lines and filter all got replaced (at the same time) to be able to get it running back in December and i only run gas that has no ethanol. and OBD I doesnt store codes
sure does store codes renix does not
Old 09-03-2011, 12:54 AM
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hmmm didnt know obd I stored codes, a plugged cat could be possible since i have been running no muffler for 3 months
Old 09-03-2011, 01:00 AM
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Turn your key on off on off on in 5 seconds and the cel will flash. The number of flashes followed by a pause indicates the code. You need a list of codes though. Might be in haynes or chiltons.
Old 09-03-2011, 01:17 AM
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Sounds a little like this story:

My 90 started all sorts of ruckus. The whole works. It would hesitate, miss, pop back out the intake. (the confetti blowing out the grille is how I found the mouse nest in the air cleaner). No start a few times. Run like a (frightened) ape if you floored it, but stumble on even throttle. Or run fine for days. Found that most of the usual suspects all seemed to be about $50 each, and some are a ***** to change. I didn’t want to just throw money I didn’t have at it, so I just did normal tune up stuff. Odd symptom (you may or may not have). Could start and run all day , no problem. Turn it off for 2 minutes then “the tantrums”. The sitting business really had me. Oil dripping around the CPS sensor, engine heat migrating to the coil or TPS or something? Something involving the manifolds and a vacuum leak? Catalytic converter. Had to be heat migrating while it was off. It took over a year to figure out that the heat shield over the manifolds was expanding into the injector wires at the front. I moved the wires, piece at last!
Old 09-03-2011, 04:10 AM
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Check the ground on the TPS and the distributor it could either be out of time or loose, the knock sensor is a possiblity to.


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