Hey, I am having a problem when I accelerate at high RPMs. Around 4-5,000 RPMs, my CEL blinks for around 5-7 seconds, but usually goes away soon after letting off the gas. However, sometimes it will stay illuminated. The code I get is P0301. I just bought the car last week so I don't know if this was a problem in the past, but the CEL does not come on at an idle or lower RPMs (2-3,000). I am bringing it to the shop to get a new flex pipe put on because it broke where it connects to the outgoing exhaust pipe. I've read that sometimes an exhaust leak can cause misfires, so this will rule that out. I'm also going to switch coil pack #1 with #2,3, or 4 to see if the problem moves with the coil pack to a different cylinder. If the OBDII reader still indicates the misfire is from cylinder #1, what would be the next step for diagnosis?

 

Could be a glazed spark plug/s.. A glazed plug will not put out a strong enough spark to light extra fuel in the mix. This will cause mis-fires.