jtlonghorn

I've got a 2000 5.3 liter 1/2 ton. Was doing 50 mph down the road when I had a substantial loss of power to the point of doing 10 mph at 3/4 throttle. When I'd back off the throttle a bit, the engine would pick up and try and run...but only for a split second. Kept running real rough and with no power until I got home (5 miles).....even put it in neutral and gave it throttle with a real rough/inconsistant response. Turned the truck off when I got home, started it up and drove 5 more miles like nothing had ever happened.

Tried to plug in the code reader, which works in my other vehicles, and it didn't work for my truck.

So.....what should I look for to fix the diagnostic plug in (fuse, etc.?)....it's the truck, not the reader that's the problem.

Once I can get it to throw a code, should help diagnose the problem.

Thoughts on why it's running so rough w/ no power? I'm thinking fuel or some sensor.

Thanks.

OLD WRENCH

A good thing to check first is the fuel pressure. Has the filter been changed recently?

country_09

maybe fuel pump is goin out? the 99-02 trucks are notorious for this. fuel pressure regulator could be goin out too..but check the filter and fuel pressure regulator first. they're the easiest

kevinkpk

Totally concur with the above. Filter however would probably not "clear up" after letting up on the throttle. I have a 2000 suburban that had a recall notice on the fuel pump several years ago. I have also replaced that pump, and regulator. great truck

jtlonghorn

Where is the fuel pressure regulator located? I'm also of the impression that a fuel pump is either all or nothing (doesn't slowly quit working).

Any thoughts on the diagnostic plug that seems to not have power to it?

Thanks.

kevinkpk

Youre dealing with an electric pump, not a mechanical anymore, those pumps "push" unlike a mechanical that pulls gas. The regulator (suburban is gone so I can't take a pix) sets on top drivers side. It is 1 1/4" or so in diameter with a vacuum hose attached. If the diaphram iis bad, pulling of the tube you will get gasoline out of it. That thing is about $50. It can cause the problems you posted, good luck!

country_09

the regulator looks like a little bulb with a hose attached to it right beneath the plastic heat shield that sits on top of the motor...now the fuel pump can go out over time, it doesn't just stop workin. mine started throwing the gas gauge all over the place and then sometimes when I would get on it, the truck would sputter and then try and go, wasn't gettin any gas. then one day it shut down on me

tech2

if fuel checks out another possibility is clogged cat.