[Bob8#Clancy]

'03 Forester, 340k miles on the clock. Been running great until recently. Gave it to my son and it promptly started running so crappy it'd barely move. Code said knock sensor, I pulled it out, tested it, put it back in, the car ran fine. Drove it 35 miles home with 3 very short stumbles. Since, it has run fine a few times, but mostly it's VERY rough, codes show misfire on 1 & 2. Cleared the codes, same thing. The knock sensor code (0328) is always there and the CEL is on whether it's running fine or poorly. When it's really bad, the CEL flashes.

The intermittent nature of it puzzles me, why run great one day, crappy the next?

Always being 1 & 2 misfiring, being paired on the coil, makes me suspicious of that.

Oh, a while before giving the car to my son, I did valves, plugs, and timing belt, and it ran fine for (probably) a couple hundred miles. Then this started.

Ideas?

MANY thanks in advance.

 

[rustfarmer]

Interesting that removing and reinstalling knock sensor seemed to help, at least for a while. The coil is the most likely culprit and as it is impossible to test it for an intermittent problem, I would replace it (with a used one if possible as a test). If the coil does not solve the issue, replace knock sensor, as once again it may test fine in static test but fail intermittently.

 

[Bob8#Clancy]

Looks like the knock sensor isn't in the picture..... the car would run fine/hardly run and nothing had been done with the knock sensor.

Replaced the coil, and it's been fine, ran it 2 times today. Kinda pointed to the coil as it was a misfire on both 1 & 2. (As [email protected] pointed out, thanks!).

 

[Kevin]

Thanks for the update!