So, I send my son to get the grand daughter from school and he will stop to fill up the van (with a 5.4) on the way. He calls me with that tone in his voice....you know the one.....dad, the van won't start.
I ask all the normal questions and he has already checked. I ask him to try again and bingo, it starts right up. He rolled home to get the GMC and the damn thing started every time I tried it. I will go to my budys shop tomorrow and use the scanner.
Sorry for the thread jack but we are already on the 5.4 diagnostic subject.
OP....looking at the numbers I would let them do it. Especially for the re-flash.
Don't know what year yours is but my 05 wouldn't start one day, wouldn't even turn over. I kept trying and trying and nada. Then I noticed another key on my key ring was resting against the ignition cylinder. Once said key was moved it fired right up. It must have causing an issue with the security chip in the key.