Charles D Scheiner

Thanks for your reply. This car has variable valve lift ( similar in effect to VVT ). I have no idea how to measure fuel trim. I am sure there is a way to monitor that with the right equipment. Does Subaru have that equipment atthe dealer? Our scan tool only shows misfire on 3 and 4 and no other codes.

I have a 2006 Outback with intermittant misfire on cyl 3 and sometimes on cyl 4. This is what we have done so far: Changed spark plugs. Changed wires Swapped fuel injectors 1 & 3 and 2 & 4 Replaced coil pack. Replaced heads and head gaskets. After doing everything up to replacing the heads, all indications were that vehicle was misfiring because it was ingesting coolant ( because of common head gasket failure in 2.5 engines) even though coolant loss was very small and took a month to drop. Compression was #1-100lbs, #2 80lbs, #3 55lbs, #4 50lbs. , Convinced that the head gaskets were the problem, we pulled the heads, and discovered minute cracks in combustion chambers. We replaced the heads and after working out initial bugs, vehicle idled like new, smooth and quiet. But when driven it seriously lacked power. Fearing we had gotten the timing belt marks wrong, we disassembled and checked, but marks were spot on. After checking for clogged convertor ( by removing upstream O2 sensor and checking for excessive back pressure) we needed to reset codes. We reset codes and let it idle for 20 minutes. Perfection. Shut it off. Eat dinner. Go to take vehicle and we have misfire on 3 & occasionally on 4. Car is undrivable. My son says it is exactly what was wrong before we did anything. He also says that in the morning, after carhas cooled down, it will probably start and run fine. I will check in the morning. Suggestions?