Thanks for the question! Yes, you can add Sea Foam to the gas tank. I’d recommend adding High Mileage in a strong cleaning dose. If the rough running is related to a dirty fuel system, High Mileage will help. If not, it will narrow down the potential problem by process of elimination. (That said, note that we always recommend having a vehicle diagnosed at a reputable vehicle repair facility if you are concerned about the vehicle’s operation.)

Here’s what I’d do: wait until the tank is low (1/4 -1/8 tank), add the whole 16 oz can, and then drive for at least 10-20 miles before refueling. It’s safe to add a high concentration like that and it works very well for cleaning fuel residues and deposits.

Let me know if you have any other questions! Happy to help!

Hi Louis,

Yes, you can add it to less than half a tank of gas. In fact, adding a full 16 oz can to a low tank is a very efficient and effective way to use Sea Foam. I like to wait until the tank is low (1/4 -1/8 tank), add the whole 16 oz can, and then drive for at least 10-20 miles before refueling. It’s safe to add a high concentration like that and it works very well for cleaning fuel residues and deposits. Add it to fuel like this every 3,000 miles or once a year.

Thanks for the question, Al.

It’s better to add a full can to a low tank of fuel. I like to wait until the tank is low (1/4 -1/8 tank), add the whole 16 oz can, and then drive for at least 10-20 miles before refueling. It’s safe to add a high concentration like that and it works very well for cleaning fuel residues and deposits. Add it to fuel like this every 3,000 miles or once a year.