I have the 3.4 v6 in my 90 trooper and have finally put the bigger throttle body on it. I had the bigger injectors in my old 2.8 throttle body, but the bigger body with the injectors definitely performs a lot better and gets better gas mileage. I set the TPS at .5v and idle is at around 700 right now, but it still occasionally dies on me when I go in reverse or am at a stop light.

So I think the fuel pressure is the culprit. Now my question is how do I adjust this? I still haven't put a fuel pressure gauge on it, but will as soon as I have time away from school. I know you can play with the spring, and the spring I am using is new from a rebuild kit. So what is the best way to adjust the fuel pressure if there is a different way then stretching the spring?
Thanks

Here's some info that should help:

http://www.s10planet.com/forum/showthread.php?t=17779

http://www.aces.edu/~parmega/efi/tbi_adjust.htm

http://www.howstuffinmycarworks.com/GM_TBI_fuel_pressure.html

sweet thanks Ed. I still can't tell what the best way to test the fuel pressure is on my trooper. What do you guys do to get a fuel pressure gauge on there?
Thanks,
Kyle