Hello all.. I'm reaching out because I need some help troubleshooting my truck please.
I have a
Year: 2006
Model: F150
Drive: 2wd
Engine: 4.2L V6
Mileage: 142k

Around the end of March I got a check engine light. Didn't think much of it and cleared it (I figured it was because I recently had to disconnect the battery for a while)..
About a week later I got another check engine light. Looked into it and got:

B1352: null
P0171: System too Lean (Bank 1)
P0302: Cylinder 2 Misfire Detected
P0316: null
P1000: OBD-II Monitor Testing Incomplete

I did some research online (google, YouTube, and here)..
I'm not too sure about the vehicle's past history, as it was "new to me" a little over a year ago.
So, I figured I'd start with the basic/easier things first..
I changed spark plugs and wires.
The problem didn't go away, still #2 misfire, & bank 1 lean (these were intermittent by the way, as I drive it 10 minutes to work, and back home, and the grocery store is just up the street).
So I got a spark plug tester and checked #2 plug. I didn't have anyone to help rev up the engine while I checked it, and wasn't able to duplicate the problem while it was in park.. (when I did get check engine, it was usually when accelerating to high speeds, also, the truck would begin to really hesitate at 50+ MPH)..

I did some more research and my next guess was the ignition coil pack.
I removed it, cleaned it really well, and did a thorough inspection of it. I couldn't find anything physically wrong with it, so I reinstalled it and was hoping maybe it was just dirty, but I still got #2 misfire & bank 1 lean..
I decided to go ahead and change my ignition coil pack.
After changing it, everything seemed to run much better... Still occasional little shake here and there at idle, but no more misfire.

Fast forward about three weeks ago, I notice the "occasional shake" was more frequent... Slowly accelerating the truck would be rough, but if I accelerated medium to heavy, no shake or hesitation (and no check engine light)..
I decided to check codes, I noticed I was still getting P0171: System too Lean (Bank 1).

I removed and checked the PCV valve, and it was letting air in through both sides... So I replaced it... Problem still there.. I did the "carb cleaner" troubleshooting for vacuum leaks (while watching RPM on scan tool), but didn't find anything.

Earlier this week I built a smoker with a jar, soldering iron, piece of rag, and mineral oil (found plans on YouTube). I hooked it up last night, and found that smoke was coming from the EGR. So I removed it, did a thorough cleaning and inspection on it, and put it back on the truck hoping it needed a good cleaning. Again, no change. So this morning I ordered a replacement EGR from Amazon (cheaper than anywhere in town, and it would get here tomorrow, vs auto parts stores said it could take 5-8 days.

(If it's NOT the EGR)
From what I've read, I'm thinking maybe the upper intake manifold gasket, or possibly an exhaust leak? But I don't want to jump into SOMETHING ELSE without some feedback.
Any and all suggestions are greatly appreciated.

Also, I'm attaching some screenshots I've taken from Torque App. For the most part, I have the screen set up where Bank 1 is on the left of the screen, and Bank 2 is on the right.
Both pictures are after about 20 minutes of driving. One is stopped at a stop light, the other is after the stop light while accelerating to 30mph.

Thank you.
This was at a stop light after driving 20 minutes

20 minutes in, right after the stop light. As I was accelerating to 30 mph.

 

Change the plenum gaskets and isolator bolts. Common issue with the 4.2 with plastic intake, mine went at 120k. I'd also throw some Techron in the gas, you may have a dirty injector on #2.

Note - I can't find a listing for isolator bolts for a 2006, maybe they changed the system.

 

Yeah, I had a feeling it was that, but was HOPING it could have been something else. I'm looking on Autozone and Rockauto, is it usually just the plenum gaskets, or intake manifold AND plenum gaskets? Is there a specific brand I should look for (or stay away from)?
Last question, what's the consensus around here for repair manual? Haynes? Chilton? I've been using AllData for a few years with my car, but if there's something better that's preferred here, I wouldn't mind looking into.

Thank you for your response!
- U

 

AllData is as good as any and better than most.

Gaskets - OEM Motorcraft or Fel-Pro. Mine was just the plenum, lower was fine. I suggest you ask a Ford tech if the 2006 used isolator bolts. If so, find a part number and replace them, they have what looks like a rubber bushing on them which dries out and cracks, causing a vacuum leak.

 

Thank you very much!
I'll check to see if it uses isolator bolts Do you have any suggestions/tips/tricks for someone planning to tackle this project?

thanks again!
- U

 

This is for 03 and earlier, yours is going to have some differences:

https://sites.google.com/site/fordf1...P0171P0174-Fix

 

Thank you! I just came across that site a few hours ago, and was going to look through it after work. :-D

 

So an update...

Yesterday evening I decided to knock out the plenum gaskets.. it took a few hours longer than I was hoping, but I changed them.. I cleaned the upper intake and the plenum as much as I could. Went through a lot of shop towels, and two large cans of carb cleaner.

While I had the plenum off, I also tried to inspect vacuum lines, but didn't see any bad ones.

I got everything put back together. It was a rough start (I'm guessing the cleaner wasn't fully evaporated? )
Anywho, I also added about 15-20 oz of techron to the tank (was currently at 1/2 full).

Drove around for a bit... First light driving, then a little bit heavy. Check engine light came on, #2misfire & lean bank 1 (i originally had #2 misfire end of March, but fixed with a new coil pack)... I cleared them hoping it was because of the rough start.

So, below are the codes I got today, while driving to and from work.


B1352: null
P0171: System too Lean (Bank 1)
P0302: Cylinder 2 Misfire Detected
P0316: null
P1000: OBD-II Monitor Testing Incomplete

I plan to double check wires this evening, but I'm guessing that the next thing it could be is the #2 fuel injector?

Thank you,
-U

 

Swap the #2 injector with one of the other ones.

 

thank you! Will do! any tricks on how to do this without having to remove the plenum again?

Also, it's been a little hectic at work, and i forgot to add some details in the update I posted a little bit ago,..
So she ran a little rough after I changed the plenum gaskets yesterday evening. But again, I assumed it was because of some of the cleaner. This morning on the way to work it didn't run/idle as rough as it has been before changing the gaskets.

And most recent update, on the way home from work just now, she seemed to be running much smoother. Acceleration didn't seem to hesitate as bad, and I didn't get a CEL.. I don't know if the weather had anything to do with it (it's been raining most of the day, and it's been in the low 70s).
I have some running around to do later today, If the #2 misfire is still there, I'll swap the #2 injector with another one this weekend.

Again, thank you for the suggestion!

- U

 

Happy Father's Day to the dads out there! 😁

so I'm starting off my father's day by tackling a fuel injector swap. 40ish minutes in, and I'm already at the plenum... It's easier after you've done it once already. Lol.. fingers crossed that everything goes smoothly...

 

sooooo...... Four of the six appear to have a crack.. might as well replace all six, right? 😒

 

New Motorcrafts are over 50 bucks each, aftermarkets and remans can be found for half that.

 

Yeah.... i just got back from walking to Autozone. i picked up the only one they had in stock. I think i'll order the other 5 online.
Unfortunately, I accidentally got them mixed them up after pulling them, but I think the one with the BIG crack was #2 (I know it WAS bank 1 side).. since my daily driver has been down since March, I need to at least get my truck (somewhat) operational.. So this will have to do until i get the rest in. Although the other three do seem to have a crack in them, they do not seem as bad at the one with the deep crack. :-\

thank you,
- U

 

I just wanted update one last time. GLC, thank you so much for the advice. My truck is running better now. :-)