nissan pathfinder code p0158 02

[falconcat]

hi there .. im new to the forum but am having problems with my 2002 pathfinder so here goes ... i hope someone can help me. in sept the code p0158 02 came up but i could not fix it at that time and it never showed up on any diagnostic after that . since then the car has been exhibiting that the engine cuts out at about 1500 rpms, {bucking } and now that code has reappeared on a scan from a transmission place. also a new code ,vc cut valve #p1491 shows up. do either of these have anything to do with the bucking and if so, which should i fix first?

[asnorton44]

Fix that 1491
Possible Cause:
- Vacuum cut valve bypass valve
- Vacuum cut valve
- Bypass hoses for clogging
- EVAP control system pressure sensor and circuit
- Hose between fuel tank and vacuum cut valve clogged
- Hose between vacuum cut valve and EVAP canister clogged
- EVAP canister
- EVAP purge port of fuel tank for clogging

[Towncivilian]

As for P0158:

You want to replace the driver's side post-cat O2 sensor. This sensor this sensor can be purchased for $53 online using discount code VISA. It is a perfect fit, and is the same brand as the original sensor. You will need a 22mm or 7/8" oxygen sensor socket and some time to replace the sensor.

[falconcat]

thanks for writing back... well .. i guess that means replace them both... so doing so will help with the bucking of the engine ? the Nissan dealership told me no... but so far 2 mechanics said yes,.. hence the cause for some confusion on the matter.. this is all a horrible headache.. also to note , a while back the code p0510 appeared which is the throttle position switch located on the top of the engine. i replaced it myself with a generic part from auto zone and had to go to nissan to adjust it.. thats when the bucking started . the transmission place said to try replacing it with a factory part and it might make a difference... obviously i should and will replace all parts but due to limited funds i would like to replace the one that is causing the main bucking problem first...and then go from there. any ideas?

[Towncivilian]

The P0158 code can be ignored until it's convenient to deal with - it will have no impact on performance or gas mileage unless the upstream oxygen sensor is failing.

The first thing I'd do regarding the P1491 is check if the hoses mentioned above are clogged. I'm not sure whether the P1491 code will affect engine performance.

[falconcat]

thanks for the reply .. i actually have delved into some of the old talks on this forum and saw one "transmission flare update!!" from 2009 .. and one person stated that she replaced a loose connection (glued it which i thought was odd) on her tps . and the surging, flaring issue stopped... interesting , since i also have experienced some issues with this little piece of plastic... can a generic part make a big difference in performance than a factory part in this matter? and can it really get loose as it is screwed in with two fairly long screws.?..are there any wires i can check as to weather their connection is solid?... i didnt look too carefully at this as being a solution because it is such a seeming insignificant little part.. too cause all this trouble with the engine lurching and bucking ... the reason i ask is because when the transmission place took it completely off the car ... everything ran smooth. can i drive the car without the thing or what ? any ideas on all this? boy, what a mystery. i might just toss this modern sensored car and go back to my 81 scrambler.

[Towncivilian]

Usually a malfunctioning TPS should throw an engine code. See EC-722 for proper operating voltages of the TPS.

Can you reach over 2400RPM?