Any ideas, help

So just took a quick ride and a couple miles down the road my ses light starts flashing, my traction-off light comes on, and the cars running ROUGH. So I pulled Into AutoZone and had them check the codes. Says p0303, the long list includes misfire cyl.3, all ignition parts(basically), vacuum leak, injector fault, hi/lo fuel pressure.

I wondered if it was misfiring on multiple cylinders, it was running very rough/little power.
Plugs & wires new last year(Ac Delco), had an extra coil swapped in position for cyl.3 no change.
Would that code/reading just show "a cylinder" that was misfiring? Not necessarily all?
I also replaced ICM, no change.
Thought these were the most likely items to be cylinder specific..

Just wanted to run it by u guys before taking it somewhere.
Thanks,
Jbird

Have you checked for a vacuum leak Jeff..That was my first thought..that or a bad coil.I have had both and the car ran like crap .Oddly it was off and on..Mostly on..lol..The coil threw a code eventually but the vacuum leak never did..Having it happen suddenly like that makes me think vacuum tho..Just my thought,,,Good luck....

Oh..Forgot to say..I wouldn't rely on it being cylinder specific too much in your search...

P0303 is EXACTLY Cylinder 3 misfire. If it had multiple misfires, it would set a P0300.
If the SES light was flashing, that means that cylinder 3 is a dead misfire. Removing a single cylinder from a V6 WILL cause it to run awful.

You need to start with the basics. Check for spark with a spark tester. Buy a cheap one if you don't have one already, hook it up to #3, and start the car. If you have spark, move on and check Fuel. If you don't have spark, check the wire, coil, and spark plug itself. I would even remove the spark plug first and visually check it.

Thanks for the responses!
I was curious whether to believe it was cylinder specific or not.
All of the things that seem to be in question are pretty new, but doesn't mean they can't be bad.
I will run down the list on cyl 3 & hope I find the fail.
Thanks again!
Jbird.

Thanks for getting me headed in the right direction!
I got a spark tester and it showed spark was getting intermittent once it warmed a little.
Replaced the plug wire #3 and running good.
It's raining so didn't get a drive in yet, looking forward to the road test pretty sure it's cured.
Thank you for the help, really appreciate it!!
Jbird