My 98 Sierra needed intake gaskets and I figured while I was there go ahead and do injectors and fuel pressure regulator. After it was finished my fuel pressure was low. Now I never checked it before the job so I had no before number to compare it to. The truck still ran real well, but only had 44 PSI idling - which everyone I spoke to said the truck shouldn't even be running with that pressure. So ruling out the new parts I dropped the tank and saw an aftermarket (Carter) pump in it and immediately figured that was the culprit. $330 later a new Delco unit is installed and I still have 44 PSI. Long story short I ended up with a defective fuel pressure regulator. It was a Borg Warner unit and upon inspection of it the diaphram was shifted about 3 millimeter further to one side causing a leak. I put a new one in today and it is fixed and has 60 PSI.

So - Inspect your new parts as best you can!!!! This $40 part cost me a lot of money and headaches!!!!!!!!

 

Thats a right on Shamrock!

 

Very good advice! Thank you.

 

I've always been taught that when you find a problem the first thing you are supposed to consider is, "Has anything been changed lately". Then work your way back through what was changed. Of course, something you just took out of the box is not supposed to be bad either. I appreciate the reminder that just because it's new doesn't mean it works. Glad you found the problem.