Fordtrucktexan

For the last few months my truck has been throwing an intermittent check engine light due to the same code every time - P0171. The dealer has allegedly checked everything and has given me the "We have done all we can do" speech. Lead tech even suggested that since today's fuels have alcohol in them, that a check engine light would be normal. The truck has been in the shop 3 times with no success or even remote possibility of what the problem could be.

The check engine light has since gone from intermittent to constant and comes back on after 5 drive cycles after clearing with an OBD2 scanner. Also, I'm now getting a P0174 code.

Personally, I think they're trying to blow me off because I'm a few months and about 2k miles away from being out of CPO warranty.

Any ideas?

Truck is a 2013 F150 Super crew 2wd 5.0 with about 45k miles.

2003XLT

No check engine light is a "normal condition" bring that truck to a different ford dealer and contact ford. It sounds like the mechanic looking at your truck is a moron/ couldn't be bothered.

New dealer and contact Ford is my recommendation

RLXXI

P0171-174 are lean codes both banks, most likely a vacuum leak, intake manifold gaskets/O-rings a common cause. You need to find a tech that knows how to chase that down. I use to quiver with hate when one of those came into my shop because they can be a royal PITA to diag. That was before I learned how to.

All I can say good luck finding a tech that can diag it properly.
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Fordtrucktexan

I went ahead and bought a 3 day subscription to the Motorcraft online Service guide (DealerConnection). Pretty awesome tool if anyone is in a jam like me, $22 for 3 days of access and it's the same software the dealer techs use.

Anyway.. I glossed over the procedure for P0171 and P0174 tonight... yea.. I see why they want me to go away. It can literally be a bazillion things triggering those codes. I have some work ahead of me.

Wannafbody

If they can't find the problem, maybe you should Lemon Law it.

RLXXI

Got a link? I lost the one I had after my sub ran out and they changed the website. I like to try to stay current for my own vehicles, my days of Ford dealer employ have long since past.
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BD0GPLATINUM

Cant you just smoke test for intake leak? Or spray starter fluid near suspected areas and listen for an uptake in the engine RPMs.

RLXXI

That's one way but the problem with that is knowing how to, cold intake O-rings do and don't leak, when hot as well but can sometimes take on the characteristics of a check valve, won't leak under pressure, but will suck air under vacuum.

Yeah it's that much of a bitch to diag. This is where having IDS installed and monitoring comes into play.
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Fordtrucktexan

motorcraftservice.com

Fordtrucktexan

I went through a can of carb cleaner doing just that tonight. Sprayed heavy around the sealing area of the intake manifold and fuel injectors. Also sprayed the vac lines from PCV to intake, and the ones after the MAF. Nothing, nada, no change to engine rpm

The diagnostic page has a section where you use the fuel trims to determine if there is a vac leak. I'm going to try that next.