Has a studder(engine)when you first pull away from stop.sometimes seems to skip a beat every know and then at idle,no miss while driveing at speed,have checked plugs wires and mass air sensor,do not have check engine light on,maby tps?

re-tune the idle mixture setting
check for vacuum leaks at the auto transmission actuator , vent controls
raise the idle rpms to around 650

If you know the plugs are fine then an ignition wire or a coil will cause the same symptom . If you had a code reader it would show you which cylinder is causing the miss. Beyond that a compresion test is needed.

The first thing to do would be to check the plugs and wires make sure they are all getting a good fire it might just have a miss in it.

If you get rough idling or the tachometer needle does not stay in one place when idling then you may have a dirty or faulty idle air control valve. This is a common cause of the problem you are describing. Other issues could be dirty MAF sensor or loose wires or vacuum hose.

Coil???????????

this is caused by slow engine idle speed, do the procedure below.
Here is the common cause of surges, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

Dead sparkplug or plug wire. Vacuum line disconnected , loose or broken,or timing / timing belt.

You say "standard transmission?" Do you mean "standard" as in "manual/5 spd./'stick-shift'?" transmission?

Either way, if you replaced the alternator belt and the battery light went away and the car doesn't sputter or stop, then it's the "speed sensor" on the transmission itself. The car will still drive, but the speedometer cannot read how fast the car is going (in RPM's as well).

fuel injector cleaner could help... maybe check the order of the plug wires, if that doesnt help i know autozone has a free computer diagnostics your car is new enough for that and it would probably be the best way of figuring this out

Your car will typically have a higher idle to offset the parasitic drag of the compressor. This is completely normal and nothing to be worried about.

The only thing that bothers me is you mentioned skipping a beat? Does this only happen under acceleration?