OT: 2010 Mazda 3

[Woodchuck]

My wifes 2010 Mazda 3 seems to have a "soft skip" when ideling and hot, seems to puff slightly through the exhaust. When it's cold there is no problem. It has thrown a P0303 code several times. If I pull either the wire harnes to a coil or injector it misses completely on that cylinder. I have changed the plugs and swapped the coils to different cylinders. (1 to 4, 4 to 3, 3 to 2, 2 to 1) with no change. When it throws a code it's still cylinder 3. I have run 3 cans of Seafoam in the tank and it hasn't thrown a code since, but still has a "soft skip" at hot Idle.
Could this be a bad injector or something mechanical like a mis-adjusted valve?
 

[thommoos]

Some of those Mazdas have solid lift valves. Therefor if it is out of adjustment it might pick up a skip otherwise pop the hood at night and check for arching plug wires, you might have to pullout and look at the based be sure to use insulated plug wires, they will light you up.
 

[thommoos]

solid valve motor, needs valve adjsutment
 

[1951 8N]

[Woodchuck]

Took the Mazda to the dealer. They said it would most likely need the engine replaced. If not covered by the warranty it would be $6,000 to $7,000. I told them if it wasn't on warranty I'd be taking it home for a junk yard engine swap.
They called this morning. It's covered and we get a loaner.
I wasn't looking forward to swapping an engine right now.