Inconsistently odd fuel delivery issues (I THINK?)

[Marky Dissod]

Although I recently recinched the intake manifold with new gaskets, I'll check it again with a vacuum gauge.
Never did try the Crank Position Sensor, which is why I'm willing to load the craposisor into the parts derringer.

 

[99Sierra2500]

I have seen them break around the ports for the PCV, I have also seen the air intake tubes get holes rubbed in them by a pulley, and stuff just loose. Who knows?

 

[Marky Dissod]

OK ...
The mech who I was hoping would be willing to diagnose this problem, categorically declared that he was unwilling to try to diagnose this particular problem,
due to its intermittent nature. Even suggested using a very hot air hair dryer that I'd lend to add heat to the fuel pump, but he said 'not this time'.

All other mechanic options are farther away & more inconvenient by bus / train, and the thought of my fuel pump quitting en route to the mech is unappealing.
Starting to like the idea of more rounds in my parts derringer. Hopefully you'd all be so kind as to help me play this game?
I'm not a mechanic, but I've enough basic tools to do pretty simple easy stuff in my 17'Long x 8'Wide x 6.5' High garage parking spot.

First shot I'll fire out of the parts derringer is the cranposinsor.
What should the next shots out of my parts derringer be? (Already cleaned MAF, swapped another throttle body, swapped another IAC motor.)

 

[99Sierra2500]

That is a bummer the mechanic isn't going to help. Next I would do what ORVietVet and others suggest is check it with a fuel pressure gauge.

 

[Tonimus]

Tape a fuel pressure gauge to the windshield and drive it around.

 

[ORVietVet]

If you don't have a long enough hose to attach to the fuel pressure gauge, do what I did. I went to my local hose/fittings supply house and they made me a custom 8' long hose with correct attachment fittings, on each end.

If it is long enough, you tape to p/s w/s and let someone else drive and you monitor the gauge. That way the driver is not distracted.

@Marky Dissod, the mechanic wouldn't even do the fuel gauge test? Maybe he didn't have a long enough hose.

 

[Marky Dissod]

That is a bummer the mechanic isn't going to help.

Think I understand his position - how is he supposed to test for a symptom he can't reliably replicate?

Next I would do what ORVietVet and others suggest is check it with a fuel pressure gauge.

That's definitely on my list.

If you don't have a long enough hose to attach to the fuel pressure gauge, do what I did.
I went to my local hose/fittings supply house and they made me a custom 8' long hose with correct attachment fittings, on each end.
If it is long enough, you tape to p/s w/s and let someone else drive and you monitor the gauge. That way the driver is not distracted.
@Marky Dissod, the mechanic wouldn't even do the fuel gauge test? Maybe he didn't have a long enough hose.

I drove around the neighborhood as he rode along with his fuel pressure gauge on the windshield and a Snap-On scanner in his lap,
but despite intentionally driving leadfoot, we were not able to replicate the symptomatic behavior,
and he was not willing to let me get on any boulevards, nevermind highways, 'cause it'd be at least 45min for roadside assistance,
and he had other cars in his queue to work on.

I know it's not the advice I'd give anyone else, but I already bought a cranposisor, and I'm trying to determine
what else I should buy that's relatively inexpensive and easy to remove & replace in a 17'Long x 8'Wide x 6.5' High garage parking spot?
If it turns out to be the fuel pump, my apt bldg won't let me drop the tank, but lightweight easy in'n'out stuff I can likely handle myself.

 

[ORVietVet]

cranposisor? What is this?

Do you mean a crankshaft sensor?

 

[Marky Dissod]

cranposisor? What is this? Do you mean a crankshaft sensor?

crank position sensor ... hodor ...

 

[ORVietVet]

crank position sensor ... hodor ...

cranposisor is 11 letters.

crank sensor is 11 letters. Same letter count and understood by all. C'mon man!

 

[Marky Dissod]

Fuel pressure never went under 48psi, which is within L59 spec.

Free Service Manual for the 2002 Chevrolet K Tahoe 4WD V8-5.3L VIN Z Flex Fuel | Operation CHARM

Detailed repair manual for the 2002 Chevrolet K Tahoe 4WD V8-5.3L VIN Z Flex Fuel, including electrical diagrams, recommended bolt torques, and estimated labor times.

charm.li

Gonna be studying all weekend, I guess ...