LanceGillette

Ok. I'll change the fuel filter and see if that helps.

We've inspected the fuel filter and it looks good. We are guessing it is injectors since the injector cleaner (Sea Foam) seems to have caused the engine to run even worse immediately after it was put in the gas.

Our Forestor (1998 with 129,000 miles) began running slightly rough about a week ago. I've replaced plugs and wires and my wife said it ran better. Yesterday I put in a can of Sea Foam in the gas tank and after about ten miles the engine quit--fortunately just half a mile or so from home. I've been able to get it started for a minute many times only to have it die. This morning it improved dramatically and I took it for a drive up the mountain. I knew I could always coast all the way home if it quit. Ran real good most of the way but when I got home it began to run bad again and now it hardly runs at all. Any suggestions on resolving the problem?

My 1998 Forester S needs a new knock sensor. Is this easy for the once a year mechanic to change?