I know there's a bit of talk on here about misfires in the first and second gen, but I was thinking my situation might be different. Might as well throw it out there to possibly save some money from the mechanics.
-2009 sport, 137k miles-
The first time my second gen fit had a CEL it was a P0301, P0302, P0303 misfire, the light turned off the next day. The second time (about a week later), I replaced all 4 spark plugs and cleared the code. About 2 weeks after that (today), the light turned on again. I'm dreading changing the coils, but I think I can do it myself. The only reason why I'm hesitating is because the misfires happened a day after getting gas, so I was thinking it could be a bad fuel injector, or maybe even a broken gas cap (looks fine to me though). Have any of you experienced a bad fuel injector?

 

Just asking for info but have you had the valve lash tolerance done? That will throw misfire codes if they're way out of spec.

 

thanks for the response. is that the same as a valve adjustment? If so, it hasn't been done. is that the next step after the coils?

 

Your codes state there's misfires in cyl 1,2 and 3. I highlighted here the most important piece of info in your post- this all started after you filled your tank with gas. There is a distinct possibility that the gas you bought was bad. The least expensive way to approach this is to burn the remaining gas in your tank and buy gas at a different gas station that sells brand name/ top tier gas.

You mentioned you replaced the spark plugs. Did you check the gap on the plugs before installation? I know a lot of plug manufacturers state their plugs are pre-gapped from the factory. Plugs get dropped and gaps change. I would double check your plug gaps and also do some searching on this forum for the updated torque to torque your plugs- which is very important. Fits have an inherent problem with plugs wanting to back out of their threaded bores- especially when under torqued. The search function here is your friend.

Before wasting money on expensive coil packs that you aren't sure are even bad, try some of the things mentioned here. If you're going to all the trouble of removing the wipers and shielding to get to the plugs and coils, as mentioned earlier here in your post, you could also check the valve adjustment while you're at it. I hope this helps.

 

It was strange because on the separate occasions I got gas, I got the new CEL with a misfire. I had gotten to empty before getting gas, and bought 89 octane gas from 3 different stations (shell, and two different chevron locations), so I kinda ruled out bad gas.

I didn't check the gaps, but I will now that you've mentioned it. Thank you so much for your input.

 

Plug torque is 20ftlbs. Dont scuff those plugs if yer checking the gap on anything fancy. iridium. maybe platinum. They say not to (at least i'm certain that's the case with iridiums) because the coating is thin and can scrape off..

Good news, nothing you've got lined up to inspect is too harrowing. If concerned about fuel, dump an additive bottle in there. I've used lucas, seafoam, techron ect. They all seem exactly the same to me. They lube stuff and help any goop in the fuel system pass through and get burned, but shell and chevron, unless theyre dumpy spots, all should have good fuel.
I expect loose plugs and would be surprised if three coils went bad at the same time. Valve adjustment is nice too! Little engine tuning to make em run pretty