Hi guys.. I have a 97 blazer and my wife has a 2000 jimmy.. anyways i picked up a snap on fuel pressure gage so off course i wanted to try it out.. So i screw the fuel gage to the valve and turn the ignition on to prime and there is no pressure. Im thinking i got screwed with the gage. Well, i started the truck and the pressure goes to about 58 psi. I shut the engine off and the gage instantly goes to Zero... Now i am confused. .. Well, wondering what was going on, i screw the gage to my wifes truck... it primes to like 55psi.. i start it and its about the same alittle more.. and shut it off and it stays constant.... What is wrong with what i did.my truck runs fine .Is the procedure different for both? Last year i replaced the injectors with the new design, and two years ago installed a replacement carter pump but i have no problems. Thanks for your help.

 

Are you sure you were holding your mouth right?
Seriously, I can't imagine why it was reading on yours like that if the truck is running correctly. I would test it a couple more times and see if it does the same.

 

Is it possible you screwed it in on the down stream side of the regulator?

 

I connected it the the valve near the distributor . It is on the same location on both vehicles . It has a black cap. I will try it this afternoon once again..