This originally started as a Knock Sensor CEL code thread titled High-pitched whine, jerky acceleration, rough idle, check engine light
I've since replaced the knock sensor but when I went to clear the code there was a second code; P0304- Misfire Cylinder 4.
Wires look great (OEM Subaru) and I believe they were changed at 60k but just to double check, I swapped the cylinder 4 wire with cyl. 2 and cleared the code. Code came back about 5 miles later as cyl 4 misfire (P0304).
I do tune ups regularly and plugs look mint (just checked)!
I need some advice as to what to check next? I've read that there's a pretty simple technique to checking the ignition coil but I don't have a manual. Can someone give some steps for coil diagnosis?
Also, what else should I be looking for?
Worst case is it's the valves from what I've read
Just talked on the phone w/ a buddy who has a manual. My coil appears to check out OK. Here's what we did: Measure resistance between the 1-2 coil terminals @ 13.6Kohm and 13.9Kohm between terminals 3-4. Spec is IIRC between 10-15k. Also Ohm'd out all the wires and they're within spec.
Edited by 211, 16 June 2009 - 07:39 PM.
resolved issue- updating