What would cause the 15 amp EFI fuse under the hood to blow?

I'm driving along after about an hour, poof, the truck dies instantly. I drift off to the side of the road and start to evaluate. She cranks, power to everything, check fuses, and the EFI is blown. i swap it out to see if it would blow again. Nope! Clean running the rest of the hour home and hasn't missed a beat.

Any ideas?

 

make sure your o2 senor harness has not fallen into the exhaust

 

yep. Mine blew when some tweaker stole my cat converter; I drove it home for 37 (loud) miles and the next day after I was trying to start it, wouldn't budge/turn over at all. pissed off already, that didn't help things.

Finally checked my fuses after running out of options and whola! EFI fuse blown. I guess when the O2 sensor is compromised, it likes to pop that fuse. Replaced fuse, ran fine ever since.

If you've got more than 100k on the O2 sensor, time to change it anyway.

 

well, guess I should say, replaced cat converter, then fuse, then workie... ran the O2 sensor out in the breeze so to speak to get home sans cat.

 

Really it is hard to say since it ran fine after it was replaced.

for some reason that circuit had a higher then normal current draw.

loose connection ?? Hit a big bump in the road??