Sometime when I start to five my jeep gas, it starts to accelerate a little, but then the power just cuts out. my C/E light is on for high voltage o2 sensor. But i've checked my sensors and they look ok.. How do I fix my o2 problem? and is my o2 sensors really screwing with my power and acceleration that much?

 

An O2 sensor can look fine on the outside and be worn out/not operating properly on the inside. The 'upstream' or pre-catalytic converter) O2 sensor reads your exhaust gasses rich/lean condition and sends a signal to the PCM which adjusts fuel flow. They wear out over time and can be eratic. I wouldn't think the O2 sensor being bad would be that noticeable tho. If you disconnect it and run the engine, the PCM will adjust to default settings. Drive it with the O2 sensor unplugged. If the problem goes away, the sensor is bad.. replace it. If the problem remains, the O2 sensor should be ok. I'd replace it anyway. They're cheap and should be replaced regularly. I would check your TPS (throttle position sensor) They're easy to test with a VOM, and could also cause your problem. Keep us posted

 

The lights still on and the acceleration is still terrible. I replaced my upstream sensor about 4 or 5 months ago maybe.. I wouldn't imagine that it needs to be replaced already.. I noticed a hole in my cold air intake right where it goes into the throttle body. I thought that maybe it was sucking in too much air and that was throwing things off. you know maybe bringing in too much air and it was throwing in too much gas causing my bad milage and my sub par acceleration, but nothing seems to fix anything.

 

Your coolant temp sensor can make your jeep do funny things. I would get a scanner that has a live scan mode(i think thats what its called) and you can go through and look at each sensor(i think) and see if there all working properly. A sensor can be stuck in one position but wont throw a error code so you have to look at it while your engine is running to see if its reading properly.

 

I dont think its my coolant temp sensor, my temp seems to read ok at 210 and feels hot coming out of the vents.

 

Mine read fine too but every so often my jeep would sputter and cut out. It only did it once in a blue moon. I could never figure out what it was untill it finally threw a code one day.

 

What it an expensive fix? Do you think my MAP sensor could be screwing with things?

Those three wires that go into that black box right by the intake manifold is my MAP sensor yeah? Should I clean it? I even heard of maybe just getting rid of it??

 

any luck? My 98 started this too, right when it shifts into 3rd it starts the chugging and bucking, does it from 42mph to 60mph, clears out and runs fine at highway speeds. Literally feels as though the fuel and fire are cutting on and off repeatedly.

 

I don't think the map sensor should be 'cleaned'. And you for sure can't just take it off. Here's a 'how to' to test it.
http://www.ehow.com/how_4478865_trou...ap-sensor.html

Did you test your TPS yet? I think that's more likely to be the problem than the MAP sensor.

 

I'm 90 percent sure it's my fuel injectors. I'm replacing them soon, I'll let you know if I see a difference in the problem.

 

Like this guy said.. Mine had similar symptoms and I adjusted my tps (throttle position sensor) and BOOM!! it have way better throttle response and power increase.

 

I have a tps(new) that I havent installed yet. Got jeep from brother and he has a bit larger bank roll than I do, so he threw parts at it and I just installed them. Now its mine. Im sitting on the new tps and a new under dash ignition module/switch.........what I noticed about mine is when the hesitation, jerking starts, I can hear something under drivers side dash sort of electrical, maybe, like connection or ground shorting out/arcing. All plugs are tight and clean but i havent dropped panel to access ignition yet. Should I put on the tps first and see what happens. After these last two parts i will be in my own pockets with it.

 

BTW, Im new to Cherokee and this Forum is the S***!!!! Very nice and respectful folks over here......Having come from the JK Forum since I bought new JK in 07, its nice to see the JEEP guys from both sides of the JEEP lineup be so cool!!!!

 

If you put in a bosch or something it needed to be replaced again that day. Hopefully you went with NTK....

 

Any update on this? When I hit third gear at around 3000 rpm it starts bucking and dropping the rpms. I’ve replaces tps and cps.