I just recently (thanks to the help here) removed my dash and installed a new evaporator core (boy, what a job that was). The A/C is working nicely now, but all of a sudden I got the CEL and some hesitation when driving. Checked the codes and got P0135--O2 sensor malfunction. I know this is pretty common in Cherokees (mines a 98), but is there any way that I screwed something up in the process of taking out and puting back the dash?

thanks

 

Check your 20 amp fuse under the hood. The blown fuse was causing a high voltage CEL reading in my jeep. I replaced both o2 sensors, MAP, TPS and IAC before I figured it out

 

If you have a lift, you should look to see if the O2 sensor is damaged. I went through 3, O2 sensors because they were hitting the front drive shaft when wheelin. If it's bent of dented just a little it will fail. I had my O2 sensor relocated to the side of the exhaust instead of straight down, so it can't hit anymore. Requires a little welding. 97 jeep cherokee xj.

 

so I changed out both of my 02 sensors, cleared the CEL light (which, so far, hasn't come back on) and even reset the computer by disconnecting the battery but I'm still getting some hesitation in 2nd (it's an automatic)--but only right after I start it! Basically, I start her up, put her in drive, first gear is fine, second has some hesitation/coughing, then everything seems fine. Any ideas here???

 

im going through some trial and error repairs with my wifes pt cruiser. and ive learned it takes about 50 miles of driving before that silly light comes back on. so im betting your light will be back if its still spuddering.

 

it may well come back on, but when it was one before the only code it gave was for the 02 sensor. Is there any way something got clogged in the short time the 02 sensor was malfunctioning? (Stabbing in the dark here)