Poke911

I've been having trouble with my idle and performance. My jeep was running fine a few days ago then developed this weird issue where it hickups and loses power and eventually stalls out. I've replaced spark plugs gapped correctly, wires, ignition coil, cleaned throttle body properly, cleaned iac valve, replaced throttle positioning sensor, map sensor. I have both o2 sensors but the old ones will not come out no matter what. Tried everything. Heat, soaked in lubricant, smacked with hammer, tried a breaker bar but just bent the exhaust tube. I'm at a loss with what's going on. Really grinding my gears. Any info on what I should do would be stellar. My jeep is a 98 xj, aw4 auto, 4.0

thanks

fb97xj1

When an XJ acts up it could be dirty grounds. But not always. Look for any vacuum leaks and check for trouble codes. Even if the CEL is off, scan it anyway so you know for sure there is nothing in there that may be related to whats happening. Could be the fuel pump going out. Dont know. Whats the fuel pressure? If the o2 sensors are really that stuck, you may have no choice but to cut them off, cut a hole, and weld a new bung. Or buy new pipes.

s346k

does it run fine when the engine is cold?

Poke911

It revs high upon start up. The revs drop, runs fine for a bit, then when you press the gas it hickups/ hesitates. Then kinda revs back up by itself. Then you'll be driving down the road and it pops. Hickups. Then stalls out. It's hard to start after too I have to pump the throttle. Then rev it up and hope for the best.

dzywicki

When it stalls out will it start right away or does it need to cool off? If it starts right away that points against the crank position sensor. If it needs to cool off, then it points at the crank position sensor.
I have had weird hot idle problems that turned out to be the coil. Different symptoms than what you have though. There is a cam position sensor in the distributor that I have had cause me problems but it threw a code.
I had trouble getting O2 sensors out too. Ended up dropping the exhaust, cutting them off half way with an angle grinder, heating it up all around the bung and then getting a socket on it. Both broke free luckily.
One tip if you do drop the exhaust. If you jack up the trans and then remove the support crossmember, the exhaust can slide out the side. If it's all rusted/fused together that's a different story.

Poke911

I just changed the crank sensor literally 5 mins ago seems to run okay. Had a hell of a time trying to get it started by it went. Drove it around a bit drove well. Hoping it fixed my issue but at this point I'm not going to hold my breath. Thanks for your 2 cents I appreciate it.

dzywicki

I hope you used a quality CPS. Either MOPAR (increasingly hard to find) or Echlin. I don't know if there are any others that are recommended. There is a reason why some of them are so cheap.