Hey guys just joined and just wanted to see if someone had some insight on possible diagnosis for my 2005 5.4L Triton Excursion with 250K miles on it. The truck has been randomly stalling for about 2 months now and I cant seem to find the cause of the issue so far, it will run fine for really any given amount of time then the truck will throw a code saying Lean Bank 1 and Lean Bank 2 (sorry I cant remember the actual "trouble code" at the moment) but the truck wont always die when the code has come through the system. The truck runs perfectly and sounds perfect right up until I see my RPM drop to zero and the engine completely quits on me (all electronics stay on), I can usually give it about 2 minutes and it will start up fine and run. I have replaced the fuel filter which seemed to fix the issue for about a month and has just now came back, I have changed the air filter as well and the oil and spark plugs were changed about 3k miles ago (plan to change the oil here tomorrow). Before I forget, my Excursion is missing its cat, it was cut off about a year ago and just had a shop weld a new pipe W/O the cat (if anyone is part of the EPA I'm just kidding, it definitely has a catalytic converter). I'm at a loss at this point and figured I should come here to maybe find someone who has had a similar issue before I go tearing the truck apart and replacing things that wouldn't need replacing. Thanks for any responses I appreciate it!

G

 

Massive vacuum leak, falling fuel pump, clogged fuel filter...possibilities abound. Smoke test for vacuum leaks, fuel pressure test.

 

random shot in the dark thing i would do is check the fuel pressure but since knowing the proper parameters needed to run correctly is located in the Factory Service Manual you may as well

look up the pin point flow chart for random stall. It will walk you step by step though about 40 things to verify in the correct order.