OE is NTK

 

Yeah just looked and the sensors I got from the dealer came in a mopar package but have NTK part numbers stamped on them.

 

I'm getting the fourth sensor next week. I really hope this is the cause cuz I'm not going to be looking forward to the cost of new cats :/ fml

 

Hoping you find this out. I too have an '01 with CA emissions and the pre-cats, all the damn o2's. I recently put a new cyl head on and still have this misfire issue. Thinking it may be my exghaust as it has a loud leak. Also only misfires and runs rough on cold startups.

 

After reading and what I'm experiencing, I believe its the O2 sensors. I had Bosch in before and that didn't work. So now I have NTK on the top two and bottom front (closest to the bumper) and no longer have bank 1 codes. Since the Bosch sensor is still in the second bank, I'm.now getting a lean code there. I also have an exhaust leak but way back at the outlet of the muffler. Once I get a chance I'm going to an exhaust shop to have them weld it back up since I no longer have a welding machine.

 

Finally got the last NTK O2 sensor in today. Ran rough the first 20 minutes but smoothed out. I assume thats because the ecu was had to adjust itself. I'll update if anything changes.

 

Ugh...still the same crap. I can drive around town, to and from work with a slight rough idle and no CEL. But if I rev to 2000 rpm I almost instantly get a flashing CEL, cylinder 4 and 5 multiple misfire. Although I can't visually see any cracks in the exhaust, I'm leaning towards thinking its the gasket and or manifold thats leaking. I did discover last week that trip of my TB bolts are stripped so I'll be retapping then this weekend with 1/4-20 threads.

 

Ok so I drilled and tapped the two bolts on the TB that were stripped to 1/4-20, brand new felpro gasket and secured down. Yesterday I ran about 3/4 of a can of seafoam in through the a vacuum line on the intake manifold and lucas fuel system cleaner in the gas tank. Disconnected battery after TB was put back on and cleared the ecu memory. Took for a test drive right now and still idled rough while stopped at a red light. Engine rpm was around 630-690 when in D. Also still getting code P0174 Bank 2 System too lean.

Would an exhaust leak back by the muffler cause all this? I do have two small holes at the joints where I welded on the adapters for the new muffler and 2 1/2" pipe about two years ago.

Currently (according to readings on scanner) at idle in P, Engine RPM 730+/- 20, MAP 11.5-12.1 not getting a rough idle right now. And O2 sensors seem to be reading normally.

 

My next step is going to be new manifold gasket and flange gaskets at the pre-cats also a good inspection of the exhaust manifold for cracks especially around ports 4 and 5 where I keep getting the misfire codes.

 

Update. Just went outside to take a drive a around the block. Once I got back I parked and revved to about 1800rpm, after a few seconds I got misfire codes again on cylinders 4 and 5. Doing some research I read that a bad head gasket can cause lean condition and misfires in cylinders. I'll be putting in new head gasket and exhaust gasket next weekend and come back with results. This also might be the reason I have oil leaking around the head near the gasket area.

 

Anyone have any thoughts on this? I'm at my wits end trying to figure this out. Is the lean condition being caused by the misfire or visa versa? Id like my next step to fix the problem rather than replacing every sensor under the hood :/

 

Lean miss fires are either an injector issue or vacuum leak at intake to head gasket...

 

I'm going to go swap around the injectors from cylinders 4 and 5 in to 1 and 2 then head to the parts store for some carb cleaner.

 

So its a little too warm outside for me to be standing there messing with the injectors lol, but I went and got some carb cleaner. Sprayed around all vacuum lines, throttle body, injectors, intake manifold at the head with no change in engine rpm. On my way home from the parts store the jeep ran fine with no rough idle or misfiring.

 

Does it run worse when engine is cold?