96 Jimmy, Fuel delivery problem??

[96JimmySLT]

Hello,

My 96 Jimmy w/110K 4.3 CMFI has been acting up lately, at first it would just shut off
at idle but I could restart it and it would be fine. I replaced the plugs, wires, cap, rotor, fuel filter and cleaned the EGR (was not clogged).
It seems to start and idle good when cold but when it warms up it really hesitates on and off, especially under a load. I suspect a possible
fuel pump problem, what should the fuel pressure gauge read when engine is not running and running?
Any other suggestions??

Thanks!!

[michelq]

fuel pressure should be 60-66 psi

[96JimmySLT]

Thanks for your quick response!

Any other suggestions as to what my problem might be?

[michelq]

IT could be vacuum leak ,fuel pressure regolator ,fuel pump, timming

[96JimmySLT]

I put a fuel pressure gauge on the system and it
read 58 with just the key on and it fluctuates wildly
between 46 and 64 when is running, any suggestions??