I have a 1996 Toyota T-100 3.4L V-6 SR5 4WD. It keeps blowing the EFI fuse as I drive. It will sit and run in the driveway just fine, but if I drive for a bit, it will blow. Sometimes if I replace the fuse it will drive for a bit then blow again. Sometimes it will blow right away, but the next day (after I tow it home!) it will start and run fine. Until I drive it. I have replaced the fuel pump a year ago, just had the alternator checked, have wiggled, jiggled, squeezed + pulled on every wire in the harnesses, (yes, under the dash + in the kick panels too) clear back to the fuel tank while the truck was running, and it won't blow the fuse. Get in and drive, and ka-blooey. I just replaced the ignition switch today, and it idled for an hour, then I drove a mile, and blew the fuse. I put a new fuse in, drove 3/4 mile back and it blew again. Put another in, and it blew immediately, as did the next two. I had it towed home for the FOURTH time (I'm using up favors). How the #$#@*&& am I gonna find a short when it's this intermittant? Anyone had this kind of issue with a T-100?
PS> It doesn't blow as I am cranking the motor, but as soons as the engine fires up. It's like it switches off a "start" to a "run" circuit, then pops...

More then likely there is a wire that has worn thru it's insulation at some spot, and is shorting out, maybe after something warms up.

I know this thread is old but... ;)

Items in line with the EFI fuse are:

EFI relay
Circuit Opening Relay (fuel pump relay)
Mass Airflow Meter
Idle Air Control Valve
O² sensors (heated)