Cylinder 4 missfire, 99 Forester

[vic]

The check engine light came on. I had the codes read and they said that cylinder 4 was missfiring. I had the ignition coil, spark plugs, and spark plug wires replaced within the last 10,000 miles. The car has about 133,000 miles on it.

 

Would appreciate any suggestions.

[color-blind]

  vic said:

The check engine light came on. I had the codes read and they said that cylinder 4 was missfiring. I had the ignition coil, spark plugs, and spark plug wires replaced within the last 10,000 miles. The car has about 133,000 miles on it.

 

Would appreciate any suggestions.

 

First pull down the y-pipe and inspect the guides. It is possible that one of the guides has droped, though this is more common on the 2.2. Next perform a leakdown and compression check on cylinder #4. It is possible that you either burned a valve or have a tight valve. Make sure you find a Subaru shop that can adjust the valves with the engine in the car. Though if you burned a valve the engine will need to be pulled and the cylinder heads rebuilt.

 

In addition make sure the egr system is not sticking on. Good luck.

[Brokechump]

Can't remember if the Forester had the SOHC 2.5L, if it does you may have a possible head gasket leak? My 00 OBW got one at 120k. Of course it would have to be an internal leak to register as a missfire. White crap on the plugs would help figure that out.

 

-Dan

[tcspeer]

I had a cyclinder #3 misfire on my 2.2 engine and it turned out to be the E.C.U. Did you check to see if it is from lack of fire or gas. You can pick up a in line plug checker for just a few dollars. If you have fire then get you a noid light and check for signal to the injector. Mine would not light the noid light but it had current to the plug, so I bought the E.C.U. on a hunch and it fixed it.