I have a 1998 Subaru Legacy 2.5GT with 92,500 miles. The car has been experiencing misfires (#1 & 2 cylinders) for the last couple of years. The problem seems to occur more frequently when it is 85 °F outside or higher. Each time it misfires the dealership recommends a fix which seems to help for a while but then the misfire happens again. So far the coil has been replaced, as have the plug wires and plugs. First time the plugs were replaced with Bosch plugs by another mechanic and the misfire did not go away. Subaru dealer recommended different plugs which seemed to help for awhile. The fuel filter has been replaced. The valves have been adjusted. Fuel delivery pressure is normal. Compression test shows cylinders 2-4 at 215 psi, #1 at 205 psi which the dealer says is within tolerance. The dealer is now recommending replacing the heads. They think the problem is due to an intermittent mechanical interference and replacing all the moving parts on the heads should fix it. Has anyone else experienced this or have any other ideas?

i have a 98 subaru legacy outback, 2.5 gt with 106,000 miles on it now. just a month ago, it started misfiring, or so it says. they are the same cylinders as your misfires, 1 and 2. i haven't noticed a difference in power. i changed the plugs and wires, but no avail. if you ever get your problem fixed, let me know what you did, cuz it's stumping me.

Just fixed this problem on my 1997 2.5 and your dealer is right it does have to do with the head, and your thought about the valves was right too. My misfire on cylinder 4 was being caused because the valves weren't sealing properly, the top sides of the valves got sort of a cup in them. Had to have the head remachined and new valves put into them cost me about $1200, hope that helps.