2001 Ford Explorer Sport Trac 4.0L SOHC V6 4WD
Mileage: 98,000
Symptoms: Somewhat erratic idle, low power, below average fuel economy, popping / puffing sound in the airbox, and CEL P0171 System Too Lean (Bank 1).
What I have done in order to resolve the issue:
Yet.... it still hasn't resolved the loss of power / lean misfire. When I had the OE 90 degree vacuum fitting crack / leak, it was throwing a random misfire CEL. I fixed the hose and everything was fine for about a month of normal use. I started getting symptoms very similar to the vacuum hose leak, but after smoke leak down tests and going over the tubing with a fine tooth comb I can't find anything else that's wrong vacuum wise. It then began to throw the P0171 (Bank 1 too Lean) and mis-fire with cylinder 1. If I unplug cylinder 1 from the coil pack, the motor doesn't feel / idle any different. After replacing everything above, the only code that is left is the P0171.
It does not consume oil, coolant... I'm doubting my head gasket is on its way out. I have removed the intake manifold twice to confirm that the gaskets are in place and sealing properly. Clogged cat on the passenger side? I'm going to use a IR gun tomorrow and check the temperature to see if the cat is clogged... it would make sense in a way.... but I'm running out of options before I have to take it to a dealer.
Anyone have a similar experience or advice on how to proceed? Thanks in advance....
EDIT - How likely would a bad DPFE cause a single bank to run lean without any other current CEL?
Mileage: 98,000
Symptoms: Somewhat erratic idle, low power, below average fuel economy, popping / puffing sound in the airbox, and CEL P0171 System Too Lean (Bank 1).
What I have done in order to resolve the issue:
- Spark Plugs
- Spark Plug Wires
- Ignition Coil Pack
- Upper O2 Sensors
- Fuel Filter
- Intake Manifold Gaskets
- Air Filter (Cleaned - K&N)
- MAF (Cleaned)
- Checked all vacuum hoses for leaks. Replaced the 90 degree elbow fitting on passenger side intake manifold between coolant hoses.
Yet.... it still hasn't resolved the loss of power / lean misfire. When I had the OE 90 degree vacuum fitting crack / leak, it was throwing a random misfire CEL. I fixed the hose and everything was fine for about a month of normal use. I started getting symptoms very similar to the vacuum hose leak, but after smoke leak down tests and going over the tubing with a fine tooth comb I can't find anything else that's wrong vacuum wise. It then began to throw the P0171 (Bank 1 too Lean) and mis-fire with cylinder 1. If I unplug cylinder 1 from the coil pack, the motor doesn't feel / idle any different. After replacing everything above, the only code that is left is the P0171.
It does not consume oil, coolant... I'm doubting my head gasket is on its way out. I have removed the intake manifold twice to confirm that the gaskets are in place and sealing properly. Clogged cat on the passenger side? I'm going to use a IR gun tomorrow and check the temperature to see if the cat is clogged... it would make sense in a way.... but I'm running out of options before I have to take it to a dealer.
Anyone have a similar experience or advice on how to proceed? Thanks in advance....
EDIT - How likely would a bad DPFE cause a single bank to run lean without any other current CEL?
