Well I will get the basics out first. Truck is a 2005 FX4 screw with a 5.4 and 125k on the clock. Has an edge, everything else is stock. Plugs, fuel filter, air filter are all new.

Issue started the other day headed to the lake, as I pulled into the boat ramp the truck died. No lights nothing. Tried to restart and it would start and die almost emidietly. Put my edge back to stock and truck ran fine. Fast forward to yesterday (back on towing tune). Truck did the same at a stop light pulling the boat, but this time it fired right back up. I checked all my connections (good). Checked for vacuum leaks (none found). Truck throws no codes and runs fine except for the occasional stalling. I am really lost as to what it is. If anyone has any ideas I would really appreciate the help.

 

If it only happens with one particular tune that you may want to talk to edge or whoever wrote the tune.

 

Do a search on here for Fuel Pump Driver module.

There's a module mounted to the frame by the spare tire. They rot out, and will cause intermittent failures until finally dying at some inconvenient time.

 

I will check that, may have to get creative to get the spare tire off as I have lost the key for it.

 

THe spare tire lock punches right out. Absloutely useless gimmick, mine rusted to the point of failure in about 2 years.

 

The fact the problem seems to go away when the tune is changed would lead me to believe that it has something to do with that. Although the FPDM is notorious for failing I don't think that is it. It is possible that when you are switching tunes that the adaptive learning is being reset and has to relearn everything. Might just have to drive a little bit with the tow tune loaded. I would check with edge and let them know of your problem.

 

I agree. The module by the spare tire is to turn on/turn off the fuel pump in the gas tank. Since Ford uses only one fuel line to the fuel rails (that feed the injectors) without a return line to the gas tank, they utilize this module to turn on/off the fuel pump, which keeps the fuel at a requlated fuel pressure. There is no pressure regulater either. The reason I found for this type of setup is to prevent fuel vapor lock during high temperatures under the hood.

So, since the truck runs fine when the stock tunes are re-installed, I'd say the problem lies with the tunner and it's custom tune(s). Call the customer support group that makes the tunner.

 

Been running on just my stock tune today. Truck suddenly died in a drive thru at lunch. Guess when I get home I will have to check out my FPDM.

 

Are you getting a code? It sounds like a vacuum leak if not the tuner.

 

Nope no codes...so far it has only happened with the engine at idle.