Yesterday my service engine light came on, i plugged in my predator and got the P0304 cylinder 4 Misfire code! So i just installed the factory tune and just brought it in to dealership! Problem is when i installed the factory tune it turned off the service engine light, so am i about to waste $60 diagnostic fee or will the code still be still saved in cars computer! I had new plugs installed by the dealership a month ago btw! RT/Auto! Thanks!