ShimanoStud

So a couple of weeks ago I bought a 1999 cherokee with 118k on it, guy said that sometimes it idles rough and that it needed new injectors. So I went out and got a set of 784s off the forum. Ran it for a week and it would still idle rough but only when its fully warmed up and has been running for like an hour. Next I thought the fuel rail was vapor locking because when it would idle rough between 500-1000 rpms I would tap the gas and if I didnt feather the throttle it would bog down and almost die like its was being flooded, also the exhaust would start reeking. Once you feather it up to around 2500 rpms you could punch it and it would run rough but quickly smooth out. So i wrapped the injectors, rail, and part of the fuel line in heat tape but it still did it, still wondering if it was vapor lock I left the hood open while the engine did cool down a few degrees the idle was still rough. Finally last night I took off the throttle body and cleaned it along with the IAC reassmbled it today and drove to work 40 mins away nothing wrong. Went to lunch and never shut it off for the entire hour in the afternoon heat in florida, no rough idle or sputtering. But after driving home and sitting outside for 10 mins to see if it would mess up it did. I am clueless as to what to do next, I dont want to just start randomly replacing sensors just wondering what some others thought. BTW its a 4.0l with auto tranny and CEL is on but for an emissions leak. Please help and thanks.

salad

An emissions leak? What's the code? Sounds like your O2's toast

ShimanoStud

No it was an Emissions evap leak large and would an o2 sensor make it act like that?