ryrycars

I recently purchased this cherokee with 114k on the clock. When i got it the oil pressure sensor was bad and read no oil pressure. I changed the oil with 10w-30 and a napa gold filter when i replaced the sensor. It idles and drives at around 40psi. After doing this i got a rough spiratic idle. The jeep is a 5 speed and when shifting (not everytime its random) it chugs. It also has done it just coasting. Im thinking fuel pump? its like a jumpy chug that only lasts a second or two then goes away. Anyone have any input would be appreciated.

Gee oh Dee

Yes, check fuel pressure. Also look into plugs/wires/cap/rotor if they haven't been replaced lately.

JimZJ

I have a 98 zj and when I bought it it did the same thing and when i would stomp on it it would stop. Then one day I went to work and it chugged and stalled and wouldn't start up. I changed the crank sensor switch on the bell housing and never had a problem. I hope this helps

tjwalker

Changing the oil and the oil pressure sensor should not have any relationship to the chugging.

Follow Gee oh Dee's suggestions. Perform a FULL tuneup (Champion copper plugs gapped to .035, quality plug wires, distributor cap and rotor) and verify fuel pressure, which for your 97, should be 49 psi, plus or minus 5 psi. Many parts stores will rent you a fuel pressure gauge very inexpensively.

Simple stuff first and for a new-to-you vehicle, unless you have believable records showing it was done recently, it's time for a tuneup.....

ryrycars

Okay thanks I was planning on doing a full tuneup and already starting changing the fluids. I just thought it was odd that I drove it 4 hours home no issues then changed the oil and air filter and no I have a problem...just seams odd. But I'll go ahead and do the tuneup once I get off work and see if that fixes it.

ryrycars

Update: I completed a tuneup. Wires, plugs, dizzy cap rotor and flushed all fluids except radiator getting to that today. The chugging has gotten worse and the check engine light came on. I noticed that when it's chugging the tach fluctuates rapidly. I'm pretty much lost because it's not consistent so I'm not thinking fuel. Could it be throttle body tps that area or possible that the trasnfer case fluid I used could be wrong causes transfer case to slip?

tjwalker

The strategy for a check engine light is always the same. Pull the codes and use them for guidance.

The fact that you have a check engine light AND symptoms is not likely a coincidence.

Early 1997 XJs, you can retrieve a 2 digit code with an odometer trick, but I always recommend you retrieve the full PXXXX code using a scan tool, a code reader, or by taking your XJ to a parts store like Autozone where they will read the code for free. The full code is much more helpful in helping you to diagnose the problem.

Post the EXACT CODE here for comment (not just a description)