Ok, so my wife reported to me last week that the 100 started running rough and the check engine light came on. So when she got home I pulled up code P0304, cylinder 4 misfire. It was time for new spark plugs anyway, but in the course of replacing them I found two holes in the resonator assembly attached to the cold air intake behind the MAF, so more air was reaching the engine than was accounted for. Since a stock resonator cost more money than a new K&N cold air inake FIPK an mine was trashed, I went ahead and bought the FIIPK. Good excuse, right?
Just finished installing the FIPK and spark plugs. I had disconnected the battery per instructions during the install, so when I started it up no check engine light. However, it still ran rough. When I took it up and down the street, the CEL did come on under acceleration, but it only flashed and did not stay on. At low RPMs it does not come on at all but the engine still runs choppy. When I parked it again, the code scanner said P0300, 'random multiple cylinder misfire detected', but the check engine light is not permanently on.
Originally I had intended to replace the coil pack for cylinder four if the P0304 persisted, but now I'm not sure what to do. Any ideas?
Just finished installing the FIPK and spark plugs. I had disconnected the battery per instructions during the install, so when I started it up no check engine light. However, it still ran rough. When I took it up and down the street, the CEL did come on under acceleration, but it only flashed and did not stay on. At low RPMs it does not come on at all but the engine still runs choppy. When I parked it again, the code scanner said P0300, 'random multiple cylinder misfire detected', but the check engine light is not permanently on.
Originally I had intended to replace the coil pack for cylinder four if the P0304 persisted, but now I'm not sure what to do. Any ideas?
I'll try replacing the #4 cylinder pack. 
