Well heres the dilemma i'm facing. About a year or 2 ago, i installed an "open air intake" on my 96 4.0 XLT. I never really payed attention to it, but for the past year or so my car has been running... like crap. it stumbles, the idles rough, its always misfiring. I currently have Lean Bank 1 and Lean Bank 2 codes as well as insufficient egr flow. I was reading that the size of the intake might cause problems due to the MAF. i have cleaned or replaced every sensor i could and the EGR valve is about 2 years old.
The other day i had an Electric Exhaust Cutout installed right before my cats. I was recommended to extend my rear O2 sensor to fix the lean bank problem. Im debating tossing the stock intake setup back on to see if anything happens.

What are ya'lls opinions on this? i'm left completely lost!
Thanks!

 

By open air intake are you referring to a cold air intake with a reusable air filter, or no air filter at all? Hopefully you're running a filter.

If you have a reusable filter that uses oil to trap dust, there is a chance the oil has coated the MAF sensor elements causing or contributing to the driveability concerns. You can remove the MAF sensor and clean it using CRC MAF Sensor cleaner and see if that helps. You'll also want to make sure the remainder of the tubing after the MAF is in good shape and securely connected.

-Rod

 

I would hardly consider it a CAI... In my opinion a true cold air intake would definitely be pulling air from deep under the engine. This one is hardly 20 inches long and has the filter (yes there is a filter, no i dont oil it anymore) in the same spot as the stock would have it. I cleaned the MAF, i cleaned the intake air temp sensor, all ports are sealed.

 

When you replaced every sensor you could, did that include the DPFE sensor? These are known issues on the Explorer, Ranger, Taurus, and I'm sure a few other FoMoCo products. The DPFE is related to control of the EGR and could contribute to P0171 and P0174 codes.

-Rod

 

Yes the DPFE was replaced. Today i borrowed a vacuum test kit, unplugged the idle air control valve, started the car, unlplugged the egr vacuum tube from the valve, and then applied vacuum pressure to the valve. as soon as suction was created, the idle would drop. My Chilton manual says this means the EGR valve is working correctly. The other thing i need to check in the next few days would be the EVR i guess.

 

That's correct, that indicates that the EGR valve is working. It doesn't necessarily demonstrate that the ports are clear though to allow sufficient flow, or that the DPFE is working properly. Some folks have reported that they've had problems with certain aftermarket DPFE sensors, I don't recall if it was the plastic or metal ones they said to avoid.

-Rod

 

the DPFE i bought was plastic, so was the OEM. What do you think about the EVR?

 

Never experienced one of them failing. The one time I replaced one it didn't fix the stumble that I was troubleshooting (on my first car, before Ford had datastream mode access).

-Rod