301 misfire 07 LGT

My 07 LGT randomly misfires, and it seems to happen most on startup. Of course I usually never seem to notice when it happens. Usually I start my car and after about 2 min I leave, and notice the CEL on. Here is a history of my misfires. First one at about 60 k or so, reset it. About 5k later another one. Looked into the forum and did my 60k maintenance at the dealership. At about 75k car would not run correct without constantly misfiring under load. Took it to the dealership for waranty coverage. Dealer had the car for 30 days and started with all the small things, ie. New plug, new coil, new injector, cleaned fuel system, before they figured the valve was hanging. After I got it back it ran good but the idle was more noisy than usual. About 2k miles later all four of my cylinders misfired, I reset the code. Then another 2k miles later (present time) 301 misfire again. Any ideas or suggestions. Its not misfiring consistently like it was before, but I only have less than 5k miles before my warranty is up.

I had a P0301 on my 2006 OBXT, and it ended up being a burnt valve. This happened around 52k. Luckily it was under warranty, but if it was a bent valve, it wouldn't have been under warranty. I've gotten the P0301 code recently, but it wasn't running rough or anything, so I just cleared the CEL. Hopefully someone else can offer additional insight.

They kept finding a miss fire on the #3 cylinder at the dealer. After replacing the spark plug and the plug/clip on the coil pack they finally bought the bullet and replaced the fuel injector. Problem solved. 05 OBXT 83k miles.