My CEL had come on a week or so ago with a p0304 and a random misfire code. I guessed that it was a faulty ignition coil so I moved my coil from cylinder 4 to #1 hoping that my CEL would come back on with a P0301 which would mean its the coil. Mysteriously before I changed the #4 coil to #1 the CEL turned off and hadn't turned back on until today. I got the same exact codes so now I don't know what is wrong since its not the coil. I did a compression test over the weekend here's the #'s I got:

1. 225 psi
2. 220 psi
3. 225 psi
4. 235 psi

I did a compression test 6 months ago and all cylinders were around 230 - 235 psi. I still think the recent test numbers I got are ok but I think its strange that they are so different from a few months ago.

Anyways I also checked the plugs and they all look fine. Anyone have any ideas on this before I go to the dealership, the car is an MY 02 with 83k. Thanks.

 

Did you use the same compression tester as 6 months ago? I usually do each cylinder 2 times, and then a third if the #'s aren't close enough. This should eliminate any errors.

So you are still getting misfire codes... What you tried changing the plugs? I can't keep track when you create a new thread every time

 

Yes I used the same compression tester as 6 months ago. I tested each cylinder 3 times, the numbers I listed were an average of the three tests. I changed the plugs a few months back because on three of the plugs the bottom electrode broke off.... very strange. What I don't get is why my CEL will come on for a day or so then turn off.

 

What plugs are you running?

 

I'm using the stock NGK PFR7G-11S.