Fuel system problem?

First thing first, great site guys.

Ok I'm sure you can guess, I have a problem. I purchased a '99 Chevy Silverado 2500 4wd with a 6.0 Vortec engine about 3 months ago (180k on truck 25k on engine), and have recently ran into what seems like a possible fuel problem. I've been using low octane fuel (in case anyone was curious).

The first time it happened I was headed to work, I started losing power, so I pulled over as soon as I could, let it idle for about 10 seconds, seemed fine, turned the truck off, and restarted it and continued on. Still didn't have power, I couldn't seem to get up to 45, then it just started slowing down. every once in a while the power would kick in for a couple seconds, then it would slack off again. This has happened a couple times and I have been driving my Accord for the most part.

At low speeds it will sometimes act a little.. Jerky I guess would be the best word while trying to accelerate, it just doesn't get up and go and sometimes will top out at around 30-40.
My buddy knows a decent amount about cars and he suggested it could be a few things (fuel pump, throttle body, filter) and I was just wondering if you guys would have any other ideas. I towed it to a mechanic that I trust and they couldn't find out what the problem was because it was running fine when it made it there 2 days later. I just took it for a drive to the store and seemed like it had plenty of power. I haven't driven the truck much since this issue arose, but while I was I seemed to be getting 12-13 MPG but that was mostly city driving with a few short 50 MPH areas. I don't know if that is relevant or not.

Im sorry if this has been posted before, I ran a search and didn't really come up with anything that was too revelant (although I did learn quite a bit). I just want to enjoy driving my truck again and not have to worry about getting stuck somewhere. I hope someone can give me some insight on my problem.

If you need more info i'll do my best to answer any questions, just post here or email me [email protected]
~Travis

Sounds like your fuel pump, to me. If it hasn't ever been changed, I'd REALLY suspect that.

Also, change your fuel filter.

Filter should be easy to replace I was already planning on tossing a new one in there. I am hoping against the pump, that may be a decent repair bill LOL. I'll have my mechanic take a look at it again on Monday

I would say the filter before the pump. As the filter gets clogged, less fuel is able to get to the trottle body. there is enough fuel to start but not enough to get enhough power. Had the same problem on a 91 chevy. So I know the symptoms.

what about the fuel regulator? or I`ve read something on forums about Limp mode ?? No codes for anything here?

I think if he had problems with the fuel regulator he would have the common problem of not being to start the truck warm.

Truck hasn't had any problems starting warm or cold, i'll see about replacing the fuel filter tomorrow after work and see if that resolves the problem. and it still persists then it may be the pump. You guys are great i'll keep you updated and I know where to come next time I have a sick vehicle.