[Nick D]

Hey guys, Did my timing belt last week with a few buddies from another forum. Job went ok, putting the new belt on was kinda of a PITA even with three of us. Cam for cylinders #2 and 4 sprung around on us a couple times when were were setting time. Replaced water pump, ect too. Put car back together and all seemed well. Started up fine. Ran fine, no unusual sounds. However within a few miles the CEL cam on. P0304 (misfire on #4). Discovered that #2 and #4 wires were not clicked in all the way (had pulled them to inspect plug tube seals). Deleted code all was good. During about mile 60 of my 100 miles commute back home the CEL came back on. Same code. Came on again a few times during that week and I started to feel the misfire for the first time. A few days ago while on my lunch break I pulled #4 plug and found it to be very loose, but gap seemed ok. Reinstalled plug and wire and car ran horrible on the ride home (missing like a illegitimate offspring and this time it threw P0302 and P0304, misfire and #2 and #4). Replaced all spark plug wires with new from dealership and car ran like new. Nice and smooth acceleration (also for the 10th time deleted the P0304). To my dismay the light has return with the dreaded P0304 after about 40 miles. The car seems to be running great, what gives???

Gas mileage is normal
Current mileage is about 104,800
This is a SOHC

 

[ferret]

Did you use a Subaru Timing belt? If it was an aftermarket brand, you may be off a tooth on the 2/4 cam side. ALWAYS use the timing marks on the pulleys, NOT the belt. See my post below:

http://www.subaruforester.org/vbulletin/f88/diy-timing-belt-replacement-36818/#post423050

 

[AlleyCat]

Did you clear the original code? Once you start misfiring through a loose boot it will ruin the boot, so its good you got new wires. Did you put new plugs in too and OEM not Bosch platinum throwaway junk? Maybe lingering symptoms of a "bad" tuneup technique >or< the coil got hurt when it had to fire a large gap. BTW three (3) people are too (2) many to work on the same job on a car at once. Hope everything pans out though.

 

[AlleyCat]

Did you use a Subaru Timing belt? If it was an aftermarket brand, you may be off a tooth on the 2/4 cam side. ALWAYS use the timing marks on the pulleys, NOT the belt. See my post below:

http://www.subaruforester.org/vbulletin/f88/diy-timing-belt-replacement-36818/#post423050

Did you find the tooth pitch to be off more than a 1/16" per foot?

 

[Nick D]

I used a belt that cam in a kit. We lined the marks up perfectly. Engine runs normal. Somebody told my the wire for #4 (which I know was bad from being yanked to many times) may have toasted the plug. So monday I we replace the plugs once again (replaced last fall). I use the NGK i think they called. I just hate how Subaru has to disable the cruise when a CEL comes on. I have a long commute to work everyday and using the cruise keeps me from gaining speed over time. Sometimes if im in the "zone" I can really creep up in speed without realising it if I'm not using cruise.

 

[Nick D]

Did you find the tooth pitch to be off more than a 1/16" per foot?

Umm the marks all seemed to line up no prob. I didn't replace the plugs because they only have like 5,000 miles on them. My buddy just yelled at me and said I always gotta do both at same time. Never bothered with the wires because they always seemed fine until I took #2 and #4 off and they never seated right. My instincts tell me timing is good. Power output from the motor is normal to what is always has been.

 

[Nick D]

Installed some new spark plugs. So far no CEL. If this was the case then that would mean a loose spark plug wires would have caused a high resistance that would have killed the wire and done something to the plug to make it not fire right. Not sure just keeping fingers crossed, car seems to be running great though.

 

[Nick D]

I just want to update that my CEL is now gone! Word to the wise, if you do not get your spark plug wire boot securely clipped on the spark plugs, the high resistance seems to damage both the wires and the plugs themselves. Even though both may seem visually fine.