WorknProgress

The other night my truck began to bog down and die at 30-40mph while cruising. I had to do the old "limp home" method, having my truck continually die on me at stop lights and a loss of power steering and power brakes occurred once the truck died. The truck did alright as long as I was feeding it gas, but as soon as I let off the RPM's would lower and the truck died.

So I've researched this issue fairly well and have done the following:

-Inspected MAF sensor and all connections were pristine. I have a K&N intake and was also sure to double check and make sure the sensor was facing the right direction.

- Pulled down my spare tire and inspected my fuel pump driver module, which was also in great shape

-I recently changed a fuel filter, and went back to see if I could feel any air leaks around the connection with my hand. I did not notice any air movement while down there but I did notice a bunch of moisture coming from my exhaust joints, I'm guessing it was just condensation but it had me paranoid...

-Plugged in a port reader and had the generic "P0171 system lean bank 1" code thrown at me

The only thing I haven't done is pull apart the throttle body and clean it. However, having recently installed an intake, I had it cleaned not too long ago. I would also like to add that I have a Gryphon programmer and just last night loaded a custom tune to see if it alleviated this issue; it did not.

So that's it folks, I have no clue what to do from this point on other than limp to a shop (which I'm extremely hesitant) or have it towed. Any suggestions?

WorknProgress

Anyone?

f150corey

Im not to sure but check the fuel pump drive moduel.. Nvm just reread no clue

lariatboy

Did you clean the MAF sensor? You're introducing a whole bunch of unneeded air to the system, as well as some oil from your K&N. may consider giving the wire a shot of electronics cleaner or brake cleaner. Throw your stock intake back on and see if it clears up.

brad.fx4

check all intake seals? be sure there is no leak. I know installing CAI on these trucks automatically makes them run lean. but...not that lean!

speeddemon86

Not automatically. Mine doesn't run lean

kanga2311

Clean your MAF, check spark plugs and COP boots, use di-electric grease when you put the COPs back on. If it's not the MAF, I'm betting you have a bad spark plug or COP. Or you may have a clogged injector. Try the plugs first, though.

gone postal

It's running lean on one bank.

Not both.

Possible culprits?

Intake leak on that side, bad O2 sensor, but I doubt plugs, COPs of the MAF are causing that indication on one side of the system.

If it were the MAF I'd expect it on both sides, and if it was a COP or plug I'd be expecting a misfire and/or rich condition, not lean.

Especial86

iTrader: (1)

Have you checked all your Vaccum lines? It could be the TPS sensor in the throttle body as well... If the TB needs servicing other then a cleaning, I say just change it out.. It's cheaper then buying the TPS and servo motor separately. I also would not rule out the FPDM just yet... But this seems like it could be difficult to pinpoint.

OkaloosaFX4

"-I have a K&N intake and was also sure to double check and make sure the sensor was facing the right direction."

How long have you been running the K&N?

Have you ever had the dealer reflash your PCM for the updated strategy?

The intake could be the culprit if you do not have a custom tune to compensate for the new larger amount of air the intake is providing and the fuel delay inherent in the "drive by wire" systems in these trucks.

I tried to run the K&N intake and I was missing all over the spectrum. Took it off and the truck ran normally again. Mostly missing at WOT with the intake on. Miraculously some people on here report that they can run a CAI with no custom tune. It puzzles me how they can do this when the PCM essentially is receiving air volume data that is well above the stock range, so it physically cannot match that volume of air with the appropriate fuel levels. Furthermore, with the inherent fuel delivery delay, you sort of start behind the starting line... Too much air at time t=0, fuel delivery starts at a time greater than 0, and then the air/fuel ratio forces more of a lean condition once the fuel volume is maxed out, yet more air volume is present. Too much air and not enough fuel = burning lean = misfires and bogs. My .02.