Run through the 96+ Fuel System Diagnosis and let us know what you turn up. There are parts of that test which will tell you the status of the check valve in the pump.

You could also test the fuel pressure by disconnecting the fuel line at the filter and adapting it to the fuel pressure gauge. If it still bleeds down there, then it is a problem with the pump.

The FPR is under the upper intake plenum (plastic piece that the throttle body mounts to).

 

so i am assuming that this is a bit of a PITA to do???? i was wondering why i hadnt seen anything that looked like a FPR

 

I have done more difficult things. Tedious, yes. Difficult, not really.

The biggest pain is getting the fuel lines disconnected at the back of the block. Your first thought will be to just flex them up and out of the way, but that is a good way to frustrate yourself later on when you go to button everything back down. Once they are flexed, they can be VERY difficult to get back in.

 

yea after reading your write up it seems maybe i have a bad FPR.....it hesitates under hard acceleration and is incredably hard to start. i have to use starting fluid to get it to start. once its running its fine....but getting it started takes some starting fluid! guess ill tear into it this weekend. hope this is my issue...if so its cheaper than the fuel pump!

 

i am having the same problem with my truck and im hoping its not a fuel pump cuz god dangit the fuel pump is only 3 months old and it just started going it about a month ago
grrr highly annoying having to turn the key 5 times and needing 10 mins o crank the truck

 

the only thing that has me puzzled is if the FPR is bad.....how does it run when it wont start on its own??? it doesnt build enough pressure to start the truck but it does to run it??/ and i did noticed that if i ease into it it accelerates fine.....but if i floor it to pass someone on the interstate it'll fall on its face

 

did you ever figure out why it was doing that? was it the FPR?

 

hey Brad please post how you made out with this problem. I have a 2000 blazer 4.3 liter V-6 cental port fuel injection and am having the exact same problem. Last 10 days it won't cold start in the morning without 6 or 7 cranks and my right leg doing a dance on the gass pedal. If it starts it usually is ok for the day because I'm starting it every hour or 2 and though its a rough start it will kick over. Seems to run ok on the road after starting. But I know its going to let me down sooner or later. I'm not much of a mechanic but a guy I know tells me that in these vehicles the multport fuel injection module fails on these trucks. He said that if you remove the bolts on this module (apparently under the air plenum) which has a fuel line attached to a feed cylinder for each injector you will find the 2 closest to the rear firewall of the engine will be spotlessly clean and the others dirty and sludge ridden. He told me that when this multiport injection part fails the fuel line floods the rear 2 injectors (keeping it spotless) and allocates litltle or no fuel to the rest. Hence the flooding does not allow the truck to start without jiggling the pedal but once it starts the other injectors get the proper fuel. I would really like the opinion of a good mechanic out there if sounds feasible or like just alot of talk. Also my engine is the 4.3 liter CPI; does that still have the 6 feed fuel line to injector module? I appreciate anyone commenting because I know I'm heading for nice repair bill.

 

I too am having the beginnings of a problem like this. I really would like to know the outcome of this problem.

 

Wish I had some insight for you guys......but unfortunately I don't. I am still having the same issues with my truck. And now that it has turned off cold it has gotten worse.
I've had to use a half can to get it to start.....plus cycling the ignition to get the pump to prime. If it was indeed the spider lines wouldn't you smell gas? How could the temperature effect the FPR? If it
Could be that...I'm close to setting it on fire!