I've got a 2000 F250 with the 5.4L engine. Due to the gas prices, I bought a Honda Accord for my daily driving and use the truck once a week or so for hauling. Recently, the truck seems to not be running on all 8 cylinders / running extremely rough. It seems to get better after you drive it for a while. At first I thought it might be moisture in the fuel tank, but I try to keep the tank full. Or is there somehow it got moisture under the hood. It sits outside. I don't even know how to check the plugs since it's got the coil on plug. Any thoughts?

 

Hmmm... you may want to add some gas Stabilizer to the gas... it could just be bad gas. Also, don't forget... you might think you have a full gas tank... but you really don't. So you are still condensing some water into the tank... not at as much as if you were 1/2 full/empty though.

I don't drive my Dakota that much... and I notice that if I leave the same gas in there for more than 2 weeks, it really has a detrimental effect on the performance. Mind you, I put in 93 octane name brand gas. So I just try to use it as much as I can when it nice out. But then again, I don't road race it or anything. But I can tell when I do a middle throttle operation.

But recently I've been adding Stabilizer to the gas, and it's making the truck run a lot better after the gas has sat in the tank 2+ weeks. I add like 3 bottles of it before I shut it tight for the winter. The following spring, it would turn over first shot after sitting for 6 months, with worn copper plugs. Where as with just plain gas, it would take a few kicks to get it started, but it would start and the performance would be horrible... horrible to almost make me want to drain the gas tank.