2003 Nissan Pathfinder - cuts out during moderate to heavy throttle

[Musthavego]

2003 Nissan Pathfinder - cuts out during moderate to heavy throttle.When the accelerator is pressed about 2/3, or as you are just hitting third gear (automatic), it stumbles hard. It feels like the throttle won't open all the way and it's not getting enough fuel. It does have a K&N FIPK kit. The check engine light is on. I'v cleaned the MAF sensor with MAF sensor cleaner, but no change. Throttle position sensor? Any help would be appreciated. Thanks.

[Ramius83]

Well, a few things could be wrong.

First, your MAF sounds like it may have taken a crap. K&N filters with the oil is NOTORIOUS for killing MAFs. Cleaning it will not fix anything.

Another thing is it could be your throttle chamber. On your 2003 Pathfinder, you do not have a TPS sensor per-say. You have a throttle chamber that has a motor/TPS sensor built-in. Your Pathfinder is drive-by-wire. You press the accelerator, and a voltage is created/given to the ECU. The ECU will then open up the throttle chamber according to what amount you press the accelerator pedal. Now if the K&N oil has caked up on the throttle chamber, it could have killed it. I have seen MANY throttle chamber motors go bad because of a basic cleaning with throttle body cleaner, so I could see K&N oil doing the same thing.

So based on that, if your TB is bad, you need the whole assembly, which is very costly.

My recommendation is to ditch the K&N filter with that crappy oil, and get a standard conical air filter, or put the standard panel filter back in.

[Musthavego]

Thanks. It idles just fine, accelerates fine, but it just won't "open up." Is there a way to test the throttle chamber?