1998 4.3 i have been checking the fuel psi every other day and its on the leak down test over night tonight. its now 54 psi acording to my actron 0-100 guage and running this time it fuctuates big time from 54 to 40. i just bought the guage tonight my buddies didnt fluctuate when i was checking it before. i purged the fuel numorus times no air. i am shure its going to need a pump,to cure the high rpm break-up?

 

Yeah, 40psi is not good.

 

do the fuel presure guage usally bounce like crazy the other one i used didnt seem to do this?

 

Unless your pressure is jumping around like crazy, the other gauge you used was probably oil filled which dampens the movement of the needle.