Engine Sputtering... Fuel Filter?

Hi, all.

A little backstory. Today I replaced the fuel tank in my '01 DC. Truck has always run great, starts right up, runs smooth. The donor tank had the pump/sending unit/lines all included. Direct swap.

The donor tank had maybe a gallon of old gas in it. I got the tank hooked up, put five gallons of gas in it, and it started right up, just as it should. Ran very smooth.

After a few minutes of idling, the engine developed a slight sputter, maybe once every five seconds. The sputtering grew worse the longer the engine ran, until it became consistent.

It now sputters and shakes consistently at idle. It sputters when I depress the throttle until 2,500 RPM+, at which point it runs smoother, but still occasionally sputters.

On the road, it hesitates, sputters, and shakes heavily under load, and it definitely lacks power.

No check engine light.

Maybe it picked up some junk from the donor tank and clogged the fuel filter, or maybe an injector?

I just trailered it for a couple hours, and on the way I stopped and put Seafoam and Fuel Injector Cleaner in the tank, filled the tank, and let it idle on the trailer while I towed it, hoping the fresh fuel/cleaner may help it out. After 1.5 hours of idling, no change.

What're your thoughts?

 

Update: Replaced the fuel filter; no change.

I suspect there's water in the tank from that old ethanol gas sitting in it.

I've added K100 to the fuel, which is supposed to be great for water contamination.

 

Maybe clogged injectors? I don't know if that's a thing or Naht.

 

It's certainly possible, but the old fuel filter seemed to have sufficient flow.

I doubt there's any way something could've gotten past the fuel filter to clog the injectors?

 

Maybe the donor tank's fuel pump is bad?

 

The problem has been resolved.

After letting the K100 sit for a few hours, I took the truck for a drive. The engine ran marginally better, but still sputtered heavily while idling and while under power, and the lack of power was noticeable.

I drove it about 50 miles over dirt roads with lots of accelerating, trying to burn off some of the bad gas. While accelerating, it would occasionally have a surge of power, like it was trying to come out of it.

I eventually stopped on a straight section and floored the throttle, bringing the truck up to around 80 MPH. When I stabbed the throttle, it coughed and sputtered a few times, then surged forward and ran smoothly. Since then, it's run nice and smooth while idling and while under power. No issues whatsoever. Maybe an injector was clogged and the WOT run cleared it out? I have no idea.

 

Thanks for the feedback on the problem. I know I had some idling problems on my 04 3.4, but a new fuel filter and some seafoam (have no clue if it works or not) cleaned it up

 

In the future, when replacing a fuel tank......empty it completely. I would put dollars to donuts that the "gas" in the "new" tank was water. Since oil(gas) is lighter than oil, the water was on the bottom of the tank, which went through the fuel system. But hey, you got a topend steam clean out of the deal.