P0300, P0302, and P0304 Misfire, HELP!
I have reached my wits end with this issue. I have a 2010 Kia Rio LX and it has been experiencing some engine problems. I've had the codes scanned and it reads a P0300, P0302, and P0304 misfire. Before the problem got worse, the engine light would flash (misfire) at start up and the light would remain on while driving. It had a slight loss of power with the engine shaking rough enough to feel it, however the shaking settled down as the vehicle reached high speeds.
As it got worse, I began to experience a huge loss of power. During acceleration, the rpm would reach to about 3.25, with the engine ceasing the shake, then mellow out to a 2.8 going 68 m/hr with the engine shaking. The last time I drove it, the shaking worsened exponentially continued to misfire with little to no power. I haven't driven it since.
I had one mechanic check it out in November before it got worse, and when he removed the coil and spark plugs from cylinder 2 and 4, the spark plugs had 2 years of wear on them, even though I had changed them around May of 2016. I had another mechanic check it out (just took a look at the engines performance, and nothing else) and he suggested it might be a bad coil pack and that the engine is fine.
I can't get it to a shop, so if the problem could be fixed by a freelance mechanic, that would be great. I rather figure out what's wrong with it first before I get it fixed. Any and all help is appreciated.