Bucking like it's running out of fuel, then it'll take off!!! ???!??! @$%#$%#$%!!!!

[WmWatt]

I agree bucking is most likely an ignition, not a fuel, problem. I'd start with a good cleaning of the ignition components.

[Larry Hampton]

I swapped out the ICM and the other little module on the front side of the coil, no change either time. No condensation inside the cap either. I'm starting to believe its the pump. Like when it gets heat soaked it starts to sputter. I changed the ICM and went on a ten mile drive, it started about 6 miles into the run. Then I swapped the other module and about 2 miles into the run it started acting up.

Tomorrow I'll do a coil swap before a pump swap.

[Flyin4stroke]

I've done a couple fuel pump jobs lately. Usually they go until they stop. At least that's what I've noticed. Does that truck have 2 tanks. If so what happens when you switch to the other tank to run it?

[Larry Hampton]

Single tank. I had an '88 with dual tanks. One time the switch stopped working so I thought it was the rear pump. Dropped the tank to find one of the lines disconnected from the check valve. New check valves fixed it.

[SiliconSoul]

Any codes / CEL?

[Larry Hampton]

No codes. Just not running right.

[Jblair]

Rubber fuel line could be shredding on the inside, cheap fix. My 88 had this issue and i put extra length fuel line to make the fuel line have a swooping motion as opposed to sharp bends. . . If you pcv valve or that dumb little hose near your oil cap leak even a little it has the car run lean, im making new intake now and that sometimes gives my 90 some issues. Those hoses must fit snug. . . My 90 has thrown a CEL for FPR so if there is any issues with the actual delivery system it will usually storr a code. Id try the fuel lines. The idle woud be super up and down if it was an intake leak.

[Larry Hampton]

It wasn't the coil. Checked the plug wires and coil wire. The fuel lines are new with the fuel filter 8 months ago. I don't run ethanol.

I put 6 gallons of fuel in it and it seems to have gone away. Now it started doing this with over a quarter tank.

[bravekozak]

Remove you fuel sender, get a flashlight, look inside your tank. Replace your fuel filter sock while you are at it.

Do not use a match to look inside your gas tank.

[Larry Hampton]

I pulled the pump the other day to check for contaminants in the tank, everything looked fine.

[Larry Hampton]

You know, I'm starting to think maybe it's just the filter sock. It was bent in an upwards position. I didn't look closely at the sock itself, but there was some really fine debris in the tank, I'm wondering if the holes in the sock get full of the debris and with the sock pointed up, the fuel can't flow fast enough into the sock, so when I give it more throttle, the sock gets sucked dry at low fuel levels. I'll try replacing the sock after the first of the year at some time when it's warmer on a Saturday.

Obviously I need to pull the tank again and clean it out, which is almost impossible to do.

[Flyin4stroke]

There's a hole on the bottom of the tank with a bolt in it you can unscrew to get all the fuel out.

[drddan]

You know that there is a drain plug on the bottom of the gas tank, right?
I drained my tank to check things out when I had a problem .... luckly, mine was pretty clean, just some black stuff that looked almost like pepper in there.
I drained tank and siphoned the remaining gas and the black stuff out without removing the tank.

[David88]

It is alot of work. Not fun dropping the tank. If it were me (and Ive done it) I would spring for an ebay tank. If the tank has any rust issues at all inside, it will continue to rust no matter what. With all the work the work in getting it out I put a new one in mine. I try to justify the cost buy thinking of the money the car has save me.
On a side note, I have a coworker that drives a older gas powered crew cab silverado 50 miles one way to work everyday. I didn't do the math but it has to be between $150-200 a week in gas. Not much left of the paycheck after payin Uncle Sam and Big Oil.

[Larry Hampton]

I know about the drain plug, it's getting the contaminants out is the problem. I just had the tank boiled last spring, so no rust at all. Part of the exterior coating came off and I recoated with some roll-on bedliner.