Rough idling - 6 DTC codes

[dvishloff]

Here we go:

This is a 2001 Explorer sport 4x4, ~110k on it.
It doesn't idle rough when first started but does start to idle rough after it warms up a bit. Also, there is a unique smell once you stop driving. Sometimes you notice it in the cab, other times not. No white out the exhaust.

I am getting 6 codes as follows:
P0302 - Cylinder 2 misfire detected
P0135 - H02S-11 (Bank 1 Sensor 1) heater circuit malfunction
P1401 - Differential Pressure Feedback EGR Circuit High Input
P1130 - Lack of H02S11 Switches - Fuel trim at limit
P1131 - Lack of H02S11 Switches - Sensor indicates lean
P1132 - Lack of H02S11 Switches - Sensor indicates rich

I will be changing the spark plugs & wires this weekend (misfire #2). Will check if there is a blown fuse for the o2 sensor heater (P0135) if that doesn't work will buy a new front o2 sensor passenger side. Also sounds like I may need to change the DPFE sensor, but will try cleaning the MAF sensor first (read somewhere that a dirty MAF sensor may be an issue).

My question is this: If/When I get through all of this, what's next? #2 injector? Coil pack?

Thanks for any and all advice!

 

[gavin]

since a tune-up isn't a waste of money to begin with, and good for checking fuses first.
Although, with the number of O2 sensors on these things, before you spend money on a new O2, swap 2 sensors around. See if the code follows the O2 or if it stays in the same spot.

There are ways to check the coils without just replacing them. Same with the plug wires. Testing plug wires is just testing the impedence between both ends; should be x OHMS per foot length. Not sure of the number off the top of my head.
Testing the coil could involve testing different areas of it.

 

[swetrid]

Replace the dpfe sensor. o2 sensor and tune it up, should fix all those codes.

 

[dvishloff]

Well, changing the plugs/wires (I have had them on the shelf for a while) got rid of 4 of the 6 codes so far. The only ones left are the P0135 and P1401 after a 25 mile run. It still seems to idle a little bit rough, but if for some reason the O2 sensor is sending incorrect info to the ECU then that might be the cause of it correct?

 

[gavin]

Well, changing the plugs/wires (I have had them on the shelf for a while) got rid of 4 of the 6 codes so far. The only ones left are the P0135 and P1401 after a 25 mile run. It still seems to idle a little bit rough, but if for some reason the O2 sensor is sending incorrect info to the ECU then that might be the cause of it correct?

yep, certainly possible.

swap that front sensor with the rear sensor on the same bank.

see iwhether or not the code follows the sensor.