1997 Subaru Legacy Cylinder

Hi keclarke, Welcome to 2carpros and TY for the donation

P0304 Start by checking no.4 sparkplug, compression and injector

I did check all those things and I still get the same diognostic code. Lastnight, my check engine light came on and I did the diognostic test and it said p0304 again. What else could it be that is causing the misfire?

What's the compression reading on no.4 If all of these components tested good-possibly a wiring problem or the computer itself-Did you check the plug wire and coil resistance for this cylinder

The compression of the no. 4 is about 90 psi. That should be enought to fire. I also checked to wiring and seem to have spark. I'll check to coil resistance of the cylinder. If all that pans out, could it be a possible lifter problem? Thanks.

With that mileage -Hard to say on the lifter also try checking the no.4 injector resistances. Did you replace all the plugs

I replaced the no. 4 injector and no. 4 plug. I'll have to look at the coil resistance.

Compression pressure service limit is 128 psi. at 90 psi the compression pressure is too low and can result in misfiring.

Check the valve clearance. If it is too tight, it can result in pressure loss.