XJ don't want to climb! starts running rich

My brother has a 97 XJ with a 4.0 auto. This started happening and is getting worse! When on the trail it will start running rich , on the hard steep obstacles it will die and can't be started for about 20 minutes and runs rough, loads up and the exhuast smells like half burned fuel. It can be sitting running smooth, then just start a rough idle. It's now started doing this on the road but not as bad to point it dies and can't be started. Here's what we've replace. 2 TPSs, CPS. map sensor, air idle sensor, whole throttle body. Anybody got a suggestion, were out of ideas. thanks guys

O2 sensor.

K

What's the temperature needle showing when the engine acts up?
Is it at normal operating temperature?

MAP

Yes, we also changed the O2 sensor, I had forgot that one. The temp stays normal around 200-210. The only other thing I can think of is he said when it's running bad you can hear it sucking air more than normal, it has a cone filter. any more ideas?

Charcoal canister is full of fuel


and floods over into engine air intake on hills?

hackedxj said:

Yes, we also changed the O2 sensor, I had forgot that one. The temp stays normal around 200-210. The only other thing I can think of is he said when it's running bad you can hear it sucking air more than normal, it has a cone filter. any more ideas?

Click to expand...

Could be an intake leak - I forgot to tighten the connection from the airbox once, and it ran like a dog. Tightened up the connection so the vacuum was all working properly, and all was fixed...

I agree, it may be a vacuum leak. Check all the vacuum hose connections.
Anything connected to the manifold, brake booster... the vacuum bottle under the bumper etc... Sounds like a hose may have popped off.

If a leak exists, the ECU thinks the engine is running lean and compensates by adding more fuel to the mixture, and making it run rich.

MAP