97 Country Stalling, sputtering

My 97 Country started having issues a couple weeks ago. It would run fine on startup then start hesitating and bogging down. If I floor the gas it would clear up and come to life. It would only do it once or twice in a drive at first. Issue progressively got worst to the point it was hardly drivable, and would stall out completely. Once it stalled out the only way it would start back up is to crank it wot. Lots of smoke and gas smell.

I was getting no CEL. I replaced the TPS with a mopar unit. Went for a test drive and jeep stalled out immediately. Got it started again, and seemed to be fixed. Drove 10 miles or so, and cel came on. Code 22 temp sensor. Still running ok the rest of that evening. The next day it stalled if i let it idle or coast. I replaced the temp sensor, cleaned the plug for it, and greased it. Cleared cel, and test drove it. Jeep ran great! Probably the best it has ran since I have owned it. Parked it for the night thinking it was good to go. This morning it stumbled 1/4 mile into my drive. No cel. It cleared up and felt good again. I got on highway and cel came on. It is now throwing 21 02 sensor. Kind of to be expected I guess as rich as it was running prior to tps replacement. I will be replacing the 02 sensor. Am i missing anything else here? It is becoming frustrating when i park it running good then it acts up in the morning. TIA

an o2 sensor can cause quite a bit of trouble. the ecu usually starts reading the o2 after about 30 seconds or so.

Reading your post I was thinking O2 sensor all along. Once your done, if it bogs down under power or throws a miss fire code next, the Cat may have been damaged too but running too rich for too long. Which temp sensor was bad, coolant or intake air?

You might also clean the IAC valve in the throttle body if you have any more problems, but the O2 sensor will likely fix it.

Sorry i replaced the coolant temp sensor. I will clean the IAC and replace the 02 sensor. To be clear the only time i felt it was running rich was when it was acting up. Thanks.

Reboot the PCM and clear out all the faulty data from the defective sensors. It should like new after that, if nothing else is faulty.

This procedure will erase the 1996+ OBD-II “Adaptive Memory” stored inside the PCM and allow a new “Adaptive Memory” to be developed. After performing this procedure the PCM will re-learn and store into Adaptive Memory your engines performance characteristics. Perform these steps exactly as they are written, in the order they are written. This will cause the adaptive memory in the PCM to be erased and cause the PCM to go into Fast Learn adaptive mode.

Disconnect the POSITIVE battery Terminal clamp and touch it to ground ( not the battery negative terminal ) for 30 seconds. The engine block or the A/C compressor pump will work as a ground. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory).

Reconnect the Battery Cable
Turn Ignition Switch to the “On” position but DO NOT start the engine
Turn Headlight “On”
Turn Headlights “Off”
Turn Ignition Key “Off”

The PCM Adaptive memory has now been flashed, or erased from the PCM. When you start the engine it will be running off a set of pre-programmed tables that come with the PCM from the factory. When you get the engine up to operating temperature the PCM will start to collect data for the “Adaptive Memory”. The PCM will collect data for Adaptive Memory for the first 50 Warm-up Cycles.

Is that an OBD-II thing or Jeep-OBD-II thing?

I went and let auto parts scan codes to see which o2 sensor i needed. Got code P0138. I replaced the downstream o2 sensor. Followed steps above to "flash" pcm. Backed jeep out of garage and ket it idle for a minute. CEL came on again code 12,21,55. I flashed it again. Went for a drive. It stumbled again like before then quit. I drove for 20 minutes no cel no missing. Running good again. I am letting it cool back off and will test drive again later.

The early relearn procedure can cause it to stall and die.

Kentucky Jelly said:

I went and let auto parts scan codes to see which o2 sensor i needed. Got code P0138. I replaced the downstream o2 sensor. Followed steps above to "flash" pcm. Backed jeep out of garage and ket it idle for a minute. CEL came on again code 12,21,55. I flashed it again. Went for a drive. It stumbled again like before then quit. I drove for 20 minutes no cel no missing. Running good again. I am letting it cool back off and will test drive again later.

Click to expand...

Ecomike said:

The early relearn procedure can cause it to stall and die.

Click to expand...

That is what I was hoping. First 2 drives it cranked a bit before firing up, it had the missing issue early on both drives until jeep got to operating temp. Ran good affer that. This morning it fired right up, and ran good no issues. Fingers crossed it might be fixed. Thanks to all that replied. I will update the thread if issue returns.

the code 21 is a o2 sensor code. check that the fuse for the heater is not blown in the PDC. it maybe just be a good idea to swap the upstream sensor. the upstream sensor changes the mixtures. the downstream monitors the efficiency of the cat.

Jeep started acting up again same as original issue. Missing, popping under hood etc. No CEL. I picked up the upstream 02 sensor and swapped it out. Did a visual inspection and did find the top wire going to coil plug is opened a bit, so i dabbed some dilectric grease on it.(too close to plug to tape) Flashed the puter again. Test drive had 0 issues, but I am not holding my breath.. Will see how it does in the morning.

Ran great this morning 0 issues!

keep us posted but it sounds like you working good now.