Just thought I'd drop an info post for everyone.
My 1990 Trooper, 4cyl fuel injection, just started refusing to start.
I went through a lot of unnecessary steps because I didn't check the fuel pressure first. I did remove the fuel line and cranked the engine, and because fuel came out of the line I didn't bother to actually pressure test it.
After going in to check the timing belt/ ignition timing, distributor, etc. I finally did check the pressure and sure enough is was only a few pounds.
Anyway, if your trooper goes from running to nothing in 1 morning flat, using the fuel pressure gauge may just save you quite a bit of aggravation.