jeep not running right, i looked, please help

I made some more progress on diagnosing my jeep

i reinstalled the vacuum canister and rear O2 sensor, clear the codes ( had codes for cam sensor and O2 sensor, i replaced each)

i drove it, and it still has the same problem

it starts and idles fine. For the first 3 minutes or so, it runs fine. Then i get onto the highway and when it shifts from 3rd to OD (high rpms to low rpm) it starts to sputter. Then, I can put the pedal to the floor, and it runs great in the high rpm range. Its just at the 2000-2500 rpm range that it spits and sputters.

One other thing, once it starts doing this, it only gets worse. When i first start driving, it goes through town just fine. But after it did this on the highwa, it was spitting and sputtering in town In ALL gears. Same solution though, high RPM it runs great

i have replaced: crank sensor, cam sensor, TPS

does this sound like a fuel problem? Would a fuel problem throw any codes in OBDII??

i do not know what else to do

Did you replace the front O2 sensor? The rear O2 sensor doesn't affect how it runs. This sounds like a bad front O2 sensor.

I vote for the Coolant Temperature Sensor going bad.

Could be ing. problem.. Pull the spark plugs,dist cap,and check the wires.

Good Luck

Nick

Fuel Filter?

Brendan_91XJ said:

Fuel Filter?

Click to expand...

Yep!! X2


Nick

the coolant temperature sensor is bad? I need to replace it.

What effect would this have on the engine running?

Coolant temp sensor could make it run too lean and hard to start. For the fuel filter people, I doubt it. If the fuel filter is clogged, shouldn't you be running out of gas in high load, high RPM situations? My WAG would be coil.

It could be something in the fuel lines starving the engine, I just had a similar issue. It
started taking longer and longer to turn over, typically on the 3rd longer than normal attempt. Then while driving at 65mph, 2500rpm, the engine felt like it was surging.
The engine was not getting enough fuel, but if I put my foot into it, it would accellerate and be ok for a little while. It ended up be garbage in the lines before the filter.

benulis55 said:

...it starts and idles fine. For the first 3 minutes or so, it runs fine. Then i get onto the highway and when it shifts from 3rd to OD (high rpms to low rpm) it starts to sputter. Then, I can put the pedal to the floor, and it runs great in the high rpm range. Its just at the 2000-2500 rpm range that it spits and sputters.

... high RPM it runs great...

Click to expand...

My 97 had all those same symptoms. I tuned, cleaned, tested, and replaced this and that and it was the Coolant Temperature Sensor.

winterbeater said:

Coolant temp sensor could make it run too lean and hard to start. For the fuel filter people, I doubt it. If the fuel filter is clogged, shouldn't you be running out of gas in high load, high RPM situations?

Click to expand...

Nope, starts in open loop and use the tables in the ECU. When the temps rise enough (temp sensor) it switches to closed loop. If the temp sensor is slow to respond or has fluctuations, the ECU is getting bad feedback data .

I agree that fuel issues are not on the list of problems.