Bosbury1

Cleaned throttle body the other day and reset computer. Codes read 21 and 55 normal. The issue is when I pull up to a stop sign the car starts to shake and stalls. Sometimes it takes a minute and it runs fine then will happen again. Seems to happen at normal operating temperature. Thinking it might be the Crankshaft position sensor. Any thoughts?

lawsoncl

Chrysler ECU Computer Code 21: O2 reporting too lean or too rich. Could be a a bad O2 sensor or melted wiring to it. Did the problem start before you cleaned the throttle body? I assume you cleaned the IAC tip and the air passage for it?

Bosbury1

Yes, the problem started prior to cleaning the throttle body. About 2 weeks ago.

cruiser54

Time for more research...

Last time your Jeep got new plugs, wires, cap and rotor?

Bosbury1

During winter time when the temperature was below 40 the Jeep would take a minute or two to idle. I read that the O2 sensor has a heater pin of sorts? not sure. but if the temperature was 45 to 50 degrees no problem. Plugs, wires, cap, and rotor were replace about 6K miles ago. Purchased a new 02 sensor should be here this Friday. Also, need to bench test TPS to see if the resistance curve is correct. Will report back. Thanks.

Bosbury1

Replaced O2 sensor same issue. Will do an IAC test later today and report back. I think the issue is electrical because I drove yesterday 50+ miles no issue. Maybe the IAC is going bad.

Bosbury1

IAC test good resistance sweep within tolerance. Can a CPS sensor work and randomly make the Jeep stall? Original CPS from 1994.

Bosbury1

Replaced IAC with spare seems to fix the issue. Strange the IAC tests withing spec. Thanks

Bosbury1

Drove the Jeep today. The issue is getting worse it appears when it heats up the thing wants to stall. On the highway power goes away, if I depress the accelerator it lunges and then goes again. I'm wondering if the CPS is going out. I'm letting it sit for an hour to see what happens.

lawsoncl

Heat sensitive sounds like the CPS, but hitting the accelerator shouldn't make that better.

Bosbury1

Replaced the CPS this past Tuesday. Voila no issues. Drove today over 80 miles no issues. Thanks for the information.