My engine on my 99 forester was idling rough, and bucking a little when cold with the check engine light flashing on and off, but remaining off as the car warmed up. I gave it a tune up (without wire of course) and then my check engine light went on..the code was a cyl. 3 misfire. I don't have a repair manuel so I don't know the location of the 3rd cyl. because I don't want to take out all the plugs to check the gap, because they are a pain to get to. Can anyone tell me which is the 3rd cyl? Also if the gap isn't off, I'm still replacing the wires. If that still doesn't fix the problem, any suggestions?

Cyl. no 3 is the rear one on the passenger side.

3 4

1 2

front of engine

The problem may be due to carbon buildup. Seafoam has worked for others with this kind of problem. Pouring some into the intake and some in the fuel tank.

rachie_a,

 

Obviously check out the wiring and plug to number three first, but if that doesn't do it, this may be your next step... My 97 OBW had the same code and everything checked out fine. The service tech was stymied. Then he started pulling electrical parts and replacing them one at a time. The first thing replaced was the ignition coil, even though the old one tested out as fine. No more trouble code, and no more miss, problem solved. It may be a possibility in your case as well. Good Luck!