Fuse FI (EPI system) keeps blowing

Hi, friends
After the 4WD lights problem gone, I have a next strange thing
FI fuse (no. 10, 15A, EPI system) has blown three times within two days
How can I diagnose the problem? 

Thanks!

This is going to be a tough one - the FI fuse feeds quite a bit of stuff, and a short anywhere in there can take it out, added to that your problem is intermittent which makes it an order of magnitude more challenging.

Build your self a "fuse adapter" that replaces the fuse with low wattage 12V bulb - you're going to insert this into the fuse slot to avoid having to buy a ton of fuses - you won't be able to run the engine with it in, but, you insert it and then you're going to push/pull/flex move the fuel injection wiring whilst watching the lamp - if the movement of the wiring causes a short circuit to occur, the lamp lights instead of a fuse blowing.

Injector wiring, EGR wiring, MAF, fuel pump, anything fuel injection or emission control related - eyeball them all look for damaged wiring, chafing where it's secured , that sort of stuff.

Good luck...