2001 Pathfinder throwing CEL but no codes

[warlam]

Hello all I am a first time poster but long time reader of this forum and I appreciate all of the time many of you have spent compiling how-to guides and other information in one easy to search spot.

I have a 2001 Pathfinder that is throwing a CEL but no code( I am using a reader I have used before that has pulled correct codes for the upstream O2 sensors and CAM position sensors). The Pathfinder does not like to accelerate uphill in 4-5 gear unless at WOT. It also stumbles horribly at part throttle once it hits 4k rpm in every gear but first but if you stomp the gas to WOT it will rev to the redline unless in 5th gear as its lost so much power it tops out 80-90mph depending on the incline.

I am kind of lost at this point as to what may be the issue as I have been battling this since I replaced both upstream O2 sensors, cam sensors, fuel filter, cleaned MAF, and new spark plugs. The pathfinder only has 104k miles on it. Any advice would be greatly appreciated as to where to go from here .

Thanks

[Towncivilian]

Please provide the manufacturing date of this Pathfinder.

Try having codes pulled at an AutoZone or other parts store that does code reading.

Welcome to NICO!

[warlam]

The door sticker says Oct 2000. I will have the CEL read at Autozone next time it pops up just cleared it earlier.

[Towncivilian]

OK, you have a 2001.5 Pathfinder (same build date as mine ) which is not plagued with ignition coil packs of the 2001.0 model year. That's not to say that coil pack issues aren't possible, they are just significantly less prevalent.

[warlam]

Well that is good to know. I was leaning towards buying one of the maxima? MAFs that work but were cheaper as a while ago (over a year) I was getting lean bank CEL codes that cleared up after the O2 sensor swaps and then eventually I started getting the CEL with no code(at least not readable by my reader).

[Towncivilian]

Indeed, the Maxima MAF is still around $90 and usable in our VQ35DE equipped Pathfinders. It's strange that you've got a CEL with no codes, not even pending ones. When this occurs, the light is solid, not blinking, correct?

[warlam]

Yep solid CEL that will stay on unless cleared but have not had a code in months

[warlam]

*Update*

I decided to clean the throttle body for s*** and giggles. While I was doing so I also cleaned the MAF again. After reassembly she starts but runs rough as hell unplugging the MAF yeilds a p0100 as it should but then she smoothes out leading me to believe that my issue has been related to the MAF and lucky me I ordered one of the maxima ones earlier today before tearing the throttle body off for cleaning and then cleaning the MAF.

[Towncivilian]

I still wonder why throttle body or MAF cleaning can cause codes to be thrown. Keep us updated regarding the new Maxima MAF! I hope it solves your issues.

[warlam]

Well it didn't cause any codes to be thrown it just ran crappier than usual. Unplugging the MAF while running led to the p0100 but it also idled smoother just limited to 2500rpm. I also cleaned the contacts on the MAF sensor and plug and it ran a little better with the MAF plugged in.

[warlam]

*Update 2*

I am almost 100% sure it is the MAF at this point as I just went out to play around with it to see if I could test it somehow. I ended up unscrewing the MAF while the engine was running and turning it so the sensor inlet side is towards the front by like an extra 15-20 degrees and now she idles smooth at right about 750rpm which she hasnt for a long time and will rev up to redline eagerly. I am guessing the MAF is screwed up and cant meter the air without having it more forcefully jammed through it? I don't know that is just my guess but at least it is now drivable again until the maxima MAF gets in.

[warlam]

*Final Update*

So I just got the maxima MAF in and installed wow what a friggin difference this is the pathy I remember now she pulls hard to redline with no stumbling / hesitation like before under any throttle condition to bad it never threw a p0100 even though the MAF had s*** itself. Thanks Towncivilian and whoever discovered the cheap maxima MAF swap.

[zach7685]

I had the same issue buddy glad you caught it before it did more damage...

[Towncivilian]

Glad to be of help! Let us know if you get any more phantom codes.