Truck runs poorly - change fuel filter and it runs fine - rusty fuel tank?

1995 Nissan Pickup - 4 cyl.

I’m thinking of buying my friends truck for cheap. The issue with the truck is that it starts to run poorly like it is being fuel starved. He changes the fuel filter and it runs fine for a while, but then runs poorly again, until he changes the filter and it runs fine again.

He’s done this like 5 times now. He thinks it’s because of rust in the gas tank. Seems like a reasonable diagnoses. But I wanted to check here to see if anyone has run into this same issue but it had a different cause.

If it is caused by a rusty tank, is the only fix to buy a new tank?

Sounds reasonable so far.

Have the pressure checked and see if it’s good. You don’t know if the fuel pump works right. They might be able to check the tank if the pump has to come out. Tanks don’t always rust inside enough to make a difference.

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Define “a while”. Are you talking a day, year? I ask b/c I once had a car that was chronic complainer. Take it to the shop, or do any repair, and it ran better for a couple weeks.

You might try running it nearly empty, slosh the tank (bounce the bumper), and drain the last bit into clean pans. With luck, you’ll see some water, rust, or other contaminants. There are “sneak-o-scopes” that can peer inside the tank, but it usually is done by pulling it out.

There are several home fixes on the I-net, vinegar, coke, whatever, to remove rust, but I’d use POR-15 gas tank sealer. (There are other similar products.) Though it says it’ll seal split seams and pinholes, I’ve only used it on a tanks that was rusty, but structurally sound… and it’s 10% the cost of a new tank.

Probably a rusty tank and it would be best to just replace the tank. Maybe you can negotiate at least the price of the tank itself from the asking price of the truck.

Define “a while”…

Like two weeks.

Next time the filter is replaced empty the old one out the in coming side onto a clean white towel and see what comes out.


Are you sure it is metal . I havent seen a metal tank on a vehicle in many years .

It’s easy to check if the tank has rust.

Remove the six bolts that secure the box to the frame, and lift up the box to expose the tank so the fuel pump can be removed to inspect the inside of the tank.

That’s what I did when I replaced the fuel pump on my 95 Nissan pickup.


The easiest way to lose a friend is to sell to or buy from a vehicle .

There could be a problem with the EVAP system or the gas tank cap - causing the pump to pull against an increasing vacuum. The vacuum becomes too much for the pump to pull against after a while. Opening the system, by removing the gas cap or changing the fuel filter, brings the tank back to normal air pressure.

My friend gave me his old filter and I cut it open. It has off-white paste like stuff in it, like wood glue. What could that be?

What brand fuel filter is that?

Because I don’t see a filter end cap like on the other end.


Are you referring to the white glue that held the filter in place in its canister? If it’s a white material in the fuel, maybe a “friend” added a gallon of milk to his tank.

Next time he pulls a filter, he could see if it still “passes gas” like a new filter. It doesn’t look plugged.

The top of the filter has this white stuff caked on it, it is not glue holding the filter in place.

Sometimes kids will put sugar or sand into gas tanks as a prank. It’s also possible the gas station’s storage tank has sand in it. I had that problem in Colorado one time, made my VW Rabbit run poorly. You’re going to have to hire a shop to remove and clean the tank. I expect that – and a locking gas cap – will fix the problem. Also try to buy fuel at a name-brand gas station that sells a lot of gas.

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Could the white stuff be the result of a sealant used to attempt to fix the tank?

Ah, thanks, and that’s good news. You know the cause and how to fix it. It’s been the 60’s since I last heard of that idiot stunt. Probably no rust. When cleaning the tank, check the filler neck.

Sugar doesn’t dissolve in gas, but there is some water in fuel. That may be how some slips past the filter. It’ll burn in an engine, but leaves a deposits behind. (That’s from the one time I worked on a head, after being sugared.) He caught it as soon as he went to refill the truck.

It could be sugar and ethanol. If the problem continues it may be necessary to replace the fuel pump and clean the tank.