spark plug not firing

Hello all hope you can help me with this problem...Check engine light is on , car seems to be running a little ruff...i went to auto zone and they ran some type of check on it and said #1 plug is not firing so I changed them all ..check engine lite went out for awhile then came back on ..I then went to auto zone again and i am still not firing on that same plug ...someone told me it could be a fuel injector ..Question is what else could it be?

what year car and what engine? Was the code P0301? If so, P0301 only indicates that there is a misfire on cyl#1. As far as I know, there is no "no spark" code... and I know plenty. I just hate to say "there isn't", because when I say that, it seems like I'm usually wrong :). Don't let an auto parts store employee diagnose a problem. Get the codes and bring the code here. If they could diagnose things, they'd make much more money as an automotive technician. There's a reason they work in a parts store. "Coincidentally", they have lots of parts they can sell you.

If it was infact a code P0301, that only means that the problem is confined to cyl #1. It could be a spark plug wire arcing to ground. look/listen for sparks. Check for spark with a spark tester. If you have the 2.4L, you will need to buy a set of wires for the 2.2L (or any 4 cyl, or use 4 old but known good wires from anything else) and connect the coil assembly to plugs 2-4 and connect #1 wire to a spark tester set to 20kV. Start the engine, the spark tester should have a bright orange or blue spark in it. If you have spark on cyl#1 it is probably the injector. Check the resistance of all of them, if #1 is significantly higher or lower than the others, replace it. If the resistance is the same, check for injector pulse with a noid light.

Thats a 2.2L 1998..I did change the wires a week ago and made sure the firing order is correct..I will post later in the day with codes..thanks Mick