Q: Stalling misfiring CEL

asked by on

My 4.0L TJ Sahara had 300,000 miles on it. I hopped in to start it, and it cranked but it wouldn’t start. The Check Engine Light with codes P0340, 0135 & 1391 came on the dashboard. I replaced CKS and CPS w/ OEM but not the oil pump drive assy. After replacing those parts it started right up – then went right back to cranking with no start. No Check Engine Light or codes came up this time. I replaced the sparkplugs OEM, checked fuel pressure and did spark test. I tried to start my jeep but got a crank w/no start. Then I took it to the mechanic and the oil pump drive assy was bad which ruined the new CPS, so he replaced the assembly and installed another CPS. So I drove 30 miles home and it stalled in my driveway. The Check Engine Light came on again with code P1391. It started up right away but idled rough and stalled when rpms got low. Then the codes 0351, 0352, and 1391 came up. I installed a new coil rail and it fixed 0351 and 0352, but I still get 1391 code. The mechanic says it’s still misfiring at 2500 – 3000 rpms. The catalytic converter was shot, needs new 02 sensors and issues with the timing componenets.

I want to replace these myself, so should I replace the 20 sensors before replacing the catalytic converter? Would a bad catalytic converter ruin my 02 sensors? They are still the original ones. The components are 300,000 miles old. Couldn’t I just replace them instead of getting them tested? It is so far away where I have to get tests done. To do this I have to remove the radiator, water pump, timing chain cover, remove the gear from cam shaft and the chain; install new gear or gears and chain then put everything back in. Would that be too hard for me? Or should I let the mechanic do this? The mechanic thinks the 1391 code is probably from timing components, cats or 02 sensors which is leading to the misfiring and higher RPMs. What do you think?

Hello, thanks for writing in about your 2003 Jeep TJ. Yes a clogged catalytic converter can cause the O2 sensors to go bad prematurely. I suggest replacing the clogged catalytic converter before installing the new O2 sensors. I can’t say that the component replacement will be too hard for you because I don’t know your mechanical abilities. Your detailed description leads me to believe that you may have the necessary know-how to complete the job.

I would buy a repair manual for the vehicle and overlook the process thoroughly before attempting this. If it still feels like something you can handle, then by all means you can definitely try to do the job yourself. If you end up needing help with this, a professional from YourMechanic can come to your car’s location to diagnose your stalling issue and can replace your oxygen sensors if needed.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Stalling misfiring CEL

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: After 'check engine' light, diagnostic revealed P0171 and P0402

The first code, P0171, is an indication the engine is running lean. This code can indicate anything from clogged air and fuel filters to problems with O2 sensors and mass air flow sensors to intake gaskets. The other code,...

Q: Van shakes/vibrates after turning on and when pressing gas and brake.

Diagnostic Trouble Codes in the OBD-II regime do not identify faulty parts nor are such codes sufficient, in and of themselves, to condemn specific parts. Although vehicle parts are always referred to in the code descriptions, all that means is...

Q: Start up problem - 2001 Jeep TJ

Hello. The clicking sound you are hearing may possibly be related to the starter solenoid which is a unit located on the starter that transfers current to the starter when you turn the key. The grinding noise you are hearing...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.