Hey guys, finally got around to creating an account here and it looks like my lurking days are over! Been using this site for a while and you guys have offered more help and ideas than i could've ever imagined. So now its my turn to be the one to ask......wtf is going on with the jeep now! 98 Cherokee Sport w/ inline 6 4.0L and 4x4.... 242,000km, or 150,000 for you 'muricans....had it since 179,000km. Been a good year, put a lot of miles on it, been reliable every step of the way. But for the past month or two, its been giving me problems. Bit the bullet yesterday, bought a new distributor, cap, wires and plugs as well as a new fuel pump for er. Installed- and they've made a huge difference, fixed a lot of the uh.....imperfections....runs way better. Put 100km on it today. Only remaining issue is that occasionally when rolling on the throttle after a stop sign or red light, the jeep will pull away smoothly, rev up to about 2000rpm and then surge. Loss of power. Maybe 2-3 seconds will pass of the engine feeling suffocated and after keeping my foot steady on the throttle, it'll buck like it can breathe again and accelerate pretty quickly. Any ideas?

 

I had some similar issues, mine wound up needing a new catalytic converter. The suffocating thing was most of my issue. Good luck.

 

Did you check air filter, throttle body, O2 sensors...?

 

Air filter is good as new, ill spend some time tomorrow on the throttle body. I installed a flow master 40 series muffler, and new pipe. lets say i *relocated* the cat.... my downstream o2 sensor is zip tied up out of the way. need to find time to buy a plug and tap it back into the exhaust. the power loss issue is not consistent either, which is making it all that more difficult to diagnose. thanks for the quick responses everyone

 

Does the bogging go away if you mash the go pedal to WOT?

 

Why don't you properly install the 02 sensor then let us know if you have issues. When you stomp the pedal after a red light change your just dumping fuel into the engine as it thinks your excessively lean... the 02 sensor stuck out in free air and is not surrounded by spent gasses to give constant reading back to the ECU about fuel conditions (lean or rich).

 

Haven't had the opportunity to give it WOT when the problem appears as it always catches me off guard. Ill try and get a hold of someone with a small MIG welder and tap that o2 sensor back into the exhaust. Should update in a few days. Thanks everyone.

 

The downstream O2 sensor only monitors cat efficiency, it does nothing for fuel metering or ignition timing.

 

IJM, thank you for the correction. For my education what does the ECU do with the Cat efficiency information ?

 

Nothing other than throw a CEL if it the reading between the upstream and downstream sensors is too close. In other words, the cat isn't doing its job. It's the upstream sensor that provides feedback to the ECU.

 

In the O.P.'s 2nd post he said he "relocated" the cat whatever that means, so wouldn't putting the downstream O2 sensor be useless ?

 

O.P., read this:


https://www.cherokeeforum.com/f2/o2-...failed-222095/