Loosing power

I've got start problem couple of months. Then I found broken uderpressure air hose in fuel injection system. after repairing the starting is OK but machine lost the power and max speed is now 35 mph. It seems that vacuum leaking but now it simply die when I change to "D". Any suggestion ? Thanks at advance.
Jan

check your MAP sensor, and other air / vacuum sensors etc. & see if you can get a diagnostic tool hooked up to the EFI controller / fuel computer (since you mentioned the fuel injection system, im guessing you have E.F.I.) and see if you can't pick some fault code or something out of it. Any GM dealership should beable to assist you with diagnosis and computer readouts. You might also want to think about trying some fuel additive that will clean your intake/ injectors and related systems. The one i would try is actually a Marine (or BOAT...) additive called "Valvetect Marine performance improver". You might also want to try some octane booster just for the hell of it. Good luck with it. that has got to suck...Hope i helped ya