Hi i am pretty new here and i am just trying to diagnose problems with a 2000 chevy blazer 4.3 i recently picked up on a trade.
Idle is low and really rough and sometimes stalls
Bogs when accelerator is pressed down
has a backfire sometimes through the intake.




I recently hooked a fuel pressure test to the car it gets around 54-55 when key is turned on and off.
once it is started the fuel pressure gauge flickers from around 45ish - 52ish as seen as it is bouncing around when you give it more throttle it doesnt go up very much sometimes going down and after idling and bouncing around it dies and the pressure stays at around 46-48. until you turn key off and then back on then goes to around 54-55 i did do a leak down test and it holds the steady 55 and sometimes goes up a little after sitting 10 minutes. will a weak fuel pump be causing it to do these kind of things.

PS my gauge is brand new and i tested it on a 5.3 2000 Vortec and it does not flicker like the 4.3

Ive read that it should go up to 60 when key is cycled from on to off.

Thank you.

 

To me it sounds more like bad timing to be causing the backfire in the intake. As for the fuel pressure have you checked the fuel filter?

 

To echo AquaMan - I had this happen to me about 2 years ago with my 2003 Blazer. Turned out that fuel pressure gauge I purchased was a dud, which is awesome to drop the fuel tank twice! Before doing that, check the fuel filter - and good luck!

 

It's hard to find quality tools these days for a fair price :P