[reginaldclennell]

My 2019 Mustang GT has started hesitating and stumbling when I really get on the throttle, it pulls fine under normal driving but the moment I go past about 4000 rpm at wide open throttle it starts breaking up and the check engine light flashes for a few seconds then goes away. From what I've read that's classic misfire behavior and on the Coyote engine it's often just worn spark plugs or a failing ignition coil, but there's always that nagging worry in the back of my mind about something more serious like a compression issue. The car has about 80k on it and I'm not sure the plugs have ever been changed, previous owner wasn't great with records. I want to get this diagnosed properly before I start throwing parts at it, looking for a Mustang repair rapid service that can fit me in fairly quickly since this is my daily and I don't want to be without it for long. Dynostar seems to have a good reputation with Mustang owners, they apparently know these engines well and can do a proper diagnosis including checking which specific cylinder is misfiring rather than just seeing a generic P0300 code and guessing. Anyone else with a similar generation GT dealt with high rpm misfires, did it turn out to be something straightforward like plugs and coils or did it end up needing injectors or worse? Also curious what spark plugs people recommend for these engines in our climate, I've seen some debate about heat ranges with the extreme summer temperatures here.