96 wont start

96 4.3 auto 2wd. The story starts when I got a check engine light a month ago checked the code and it showed Running lean. Fixed a vacum line and that went away. Started having real long crank time before starts, took it in to shop, fuel pressure was fine got injestion cleaned. 2 days ago while driving I lost almost all power. Put my foot to the floor and was bareky able to do 30mph( motor just wasn't reving). But when I put it back in park it would run fine. Yesterday went out and would not crank at all. I replaced the fuel filter and plug wires and still nothing. Please, Please Help.

Im thinking its your EGR valve

would the EGR cause the no start?

i don't think so, but definitely the rough running and slow accel

#@%&!! Fuel Pump!
got it replaced today and running like a champ.

thought your pressure was fine? you didnt need to change it if it was good. plugs cap rotor would be a good start. then timing and check coil.
did you reset after check engine light problem was fixed?

call me stupid if you want

if the fuel pressure was fine and it wouldn't crank over,

then change a fuel pump then it cranks over?

there is more to it then that.

suggish engine chances are i would agree with mike egr valve is shot

Well, the fuel pressure required to run these engines is a lot higher than most mechanics would expect. He may not have known that it takes a least 55psi for the engine to operate properly. If he saw around 50psi, that would seem great by most standards, but not for the 4.3

The fuel pressure at idle may have been fine when he checked it but the pump couldn't keep up with higher demands. My truck had the same thing happen to it, didn't want to rev up very well and after a couple weeks it wouldn't go over 2500 rpm. Idle was fine through all of this.

holey &%*# 55+ lbs of pressure to run the 4.3 that seams awfuly high (expressing how shocked i am, not starting an argument)

dirty injectors? had same prob with bud's 94 jimmy

holey &%*# 55+ lbs of pressure to run the 4.3 that seams awfuly high (expressing how shocked i am, not starting an argument)

Depends on the type of injection system. Being a 96 it should be CSFI.

Key on, not running:

TBI 9-13psi
MFI 41-47psi
CMFI 58-64psi
CSFI 55-61psi

All should drop 3-10 psi while running.

make sure you check the pressure key on engine off.
if you changed fuel pump and running like crap, try a tune up and timming. let us know how it all goes or youll have alot more tring to guess.