4.3L V6 4X4/189k miles.
This is an intermittent problem but becoming more regular.
Sometimes it won't turn over, right away, unless I hold down or pump the gas. After it turns over the idle feels rough and there's some shake as if it will die but hasn't died as a result.
When I drive and apply the gas or when accelerating away from a stop, it bogs down and will vibrate and hitch a little(not violently).

Now. This has happened before. I put in 2 bottles of fuel injector cleaner and cleared up. This it didn't work as well.

I think it may be the fuel filter?

Anybody?????


Thanks!

PS
glad I found this forum.

 

Is this a TBI motor (large round air filter on top of the engine) or a CPI motor (throttle body at the front of the engine and air filter over at the driver's side fender?

If CPI, I'm suspecting a fuel leak internal to the plenum...

 

It's a CPI.
I'm suspecting a fuel leak internal to the plenum...is a little greek to me. Can you explain thatsome more?

 

The CPI motors are known to sooner or later have a leaking fuel pressure regulator which is located inside of the intake plenum. The only way to know for sure would be to pull the upper plenum off. You can diagnose this with a fuel pressure gauge by connecting it to the fuel pressure test port located on the rear of the intake manifold towards the driver's side and watching the pressure after you key-on then key-off.

You can also remove the plastic 'Vortec' cover and the manifold tuning valve (round black plastic piece with 2 bolts holding it to the upper intake plenum) and looking in to the intake. If you see pools of fuel in the lower intake, then you have an internal leak.