My car is still doing the spitting and sputtering on take off, missing at idle, and still backfiring out the intake. It goes in to satan for a new coil next week, however I was thinking, could this be the result of one or more bad exhaust valves? It kinda makes sense to me. It is also sucking gas like a thirsty whino.
Things I have tried already include:

new plugs
new wires
(these cured it for about a month, then back to crappy running)

cleaning throttle body
cleaning intake mani
cleaning combustion chambers
new fuel filter
new O2 sensors
resetting ECU

Any new ideas or input would be greatly appreciated seeing as how a few of you seem to have experienced the same problem, and must have fixed it. This is so annoying. I hate to drive my baby like this.
x(

have you taken a compression check on the car yet?
My sisters Cavalier was doing all of those things, REAL bad hesitation, sputtering, and poping somewhere in the engine bay (backfiring out of the intake?) it ended up being a cracked head.
Check the head and head gasket.
Just a thought.

had the same problem with my friends car recently. I changed his TPS and water sensor.. it's perfect now.

Got my coil pack changed today. The crappy running seems to be fixed, but I thought it was fixed before. I'll just have to wait for a couple of weeks and see...:wary