I still cant figure out the problem?

[DrewMrPimp]

I have a 1997 Jeep Cherokee 6cyl 4.0L and it runs and drives fine for awhile, but as it warms up it sometimes feels like it is running out of gas and is going to die on me. I let it coast for a minute and then I give it gas again and then it accelerates again, but sometimes with minimal power. After it almost dies a couple of times it will all of the sudden run decent again and it will drive another 2-3 miles before it does it again. It happens every so often and I have no idea what is wrong. I replaced the fuel pump, fuel filter, fuel level sending unit, and the crankshaft position sensor thinking it would replace the problem entirely, but it only made it happen less often. Ive brought it to two different mechanics and they ran diagnostics on it, but they couldnt get the problem to act up on them enough to know what was wrong. Does anyone have any suggestions or know what could be wrong? Thanks

[Jay04]

Could be a couple of issues: TPS (throttle positioning sensor), Oxygen sensor, or the MAPS

[DrewMrPimp]

Originally Posted by Jay04

Could be a couple of issues: TPS (throttle positioning sensor), Oxygen sensor, or the MAPS

There isnt a check engine light so could it still be one of these problems? This problem started a day after I blew my top radiator hose on the freeway. Could it be that the antifreeze got one of these sensors wet and fried one? Or is it possible that I have a small head gasket leak due to the radiator hose blowing and then overheating for a short period of time? The oil dipstick isnt milky like they say it should be, so I am still confused. I can bring it to another mechanic again and pay more for diagnostic time, but its slowly breaking me because we arent finding the correct problem. Thanks

[capt. apathy]

it could have a lot to do with the blown hose. most of my problems happened after an over-heat that blow the cap of the plastic reservoir.

I had problems ranging from spontaneously dieing , rough idling, dying at stops, loss of power, and poor gas mileage.

the first problem was the dying. I tracked it back to the CPS, that was failing intermittently. so I un-plugged it and started to replace it, but didn't have the wobbly I needed to reach the bolts so I plugged it back in to go buy one. the jeep ran fine all the way to the store and back (maybe 3 times longer than the best in the last 2 weeks.

so I took the connection back apart, cleaned it up, put a little WD-40 on it to help prevent future corrosion, and adjusted the plug so the pins fit tighter. I never did have to replace the original CPS, it was still working fine when my jeep was totaled 10 months later.

I then hooked up the diagnostic computer to check the readings from the other sensors (tps, cts, map sensor, knock sensor, O2 sensor, idle-air-stepper) the tps, cts, map sensor, and O2 sensor all had out-of-range, or intermittent readings (the cts said 68 F when the dash gauge was 205, keeping the ECU in warm-up mode even while overheating).

I cleaned all of the connections (they had corrosion and residue that looked suspiciously like the dried coolant left over from the over-heat)

after that the only one that was in need of replacing was the TPS, and the idle-air-stepper needed to be removed and cleaned.

so I'd advise that before you spend much cash you should clean out all of those connections and make sure the have good contact and no corrosion. then reassess your problems, you might get as lucky as I did and have most of them go away for free

[DrewMrPimp]

Originally Posted by capt. apathy

it could have a lot to do with the blown hose. most of my problems happened after an over-heat that blow the cap of the plastic reservoir.

I had problems ranging from spontaneously dieing , rough idling, dying at stops, loss of power, and poor gas mileage.

the first problem was the dying. I tracked it back to the CPS, that was failing intermittently. so I un-plugged it and started to replace it, but didn't have the wobbly I needed to reach the bolts so I plugged it back in to go buy one. the jeep ran fine all the way to the store and back (maybe 3 times longer than the best in the last 2 weeks.

so I took the connection back apart, cleaned it up, put a little WD-40 on it to help prevent future corrosion, and adjusted the plug so the pins fit tighter. I never did have to replace the original CPS, it was still working fine when my jeep was totaled 10 months later.

I then hooked up the diagnostic computer to check the readings from the other sensors (tps, cts, map sensor, knock sensor, O2 sensor, idle-air-stepper) the tps, cts, map sensor, and O2 sensor all had out-of-range, or intermittent readings (the cts said 68 F when the dash gauge was 205, keeping the ECU in warm-up mode even while overheating).

I cleaned all of the connections (they had corrosion and residue that looked suspiciously like the dried coolant left over from the over-heat)

after that the only one that was in need of replacing was the TPS, and the idle-air-stepper needed to be removed and cleaned.

so I'd advise that before you spend much cash you should clean out all of those connections and make sure the have good contact and no corrosion. then reassess your problems, you might get as lucky as I did and have most of them go away for free

Thanks Capt. Apathy! I will try some of those possible solutions first thing in the morning.

[DrewMrPimp]

Originally Posted by DrewMrPimp

Thanks Capt. Apathy! I will try some of those possible solutions first thing in the morning.

After days of frustration and almost $1000 going into my jeep, I think I have finally fixed the problem. The O2 front sensor was giving me my problems. Supposedly it took 4 hours of diagnostic time to figure out what was going wrong. If anyone has some of the problems I have stated, check your O2 sensor before spending too much money on diagnostics. Hope this helps.