If you have 55lbs. of pressure at idle then the regulator is probably good.

 

But what about the pump? It seems to drop rather low, and remember I'm not even under load, this while in park!

 

When you turn the key to the on position (dont start it) listen for the pump...it should make a hummmming noise.(hard to tell though if you have elec fans and they kick on) But if the humm is not there then its definately your fuel pump. If you dont want to hack into the pump quite yet you could always try and use some injector cleaner to see if that might do the trick!! Or better yet **** you could've gotten ahold of some bad gas...throw in some octane boost and see if it improves

 

I don't think its bad gas, because I gas up at different stations and I've had at least 4 tanks through it with the 1st tune and 1/2 with this tune. It's getting worse like I said, so who knows?

I'm going to tape the guage to the windshield and drive around while keeping an eye on the pressure.

Does anyone know what pressure these trucks are supposed to idle at, and what they're supposed to be at under load?

edit: I started it up, and I was seeing about 54psi, I pulled out into traffic, eased on to it and saw 52psi. As I kept driving (no WOT, just part throttle) it crept down to 50psi and stayed there.

 

Update: I don't think its the pump. I compared my fp readings to my mom's 02' Yukon and they're about the same. I used our fancy search button and my readings are on par with most other's. Also when I'm at WOT, until it snap, crackles, pops, bangs and shuts off, I see a consistent 60psi.

I'm questioning the tune now. I ran this setup with a stock PCM and it ran better than this!!!

 

Good find, where did you get the tune from??

 

You don't want to know, and I don't think I can say.

 

i'll say it..

Nelson.