Not sure what to do.

My kia sportage is a 98' I bought it with 32k miles 5 years old. Since then I have only had a few things go wrong. Starter 2 times, O2 sensor and the usual maintance (belts, brakes, tires,filters). It now has 51k miles and over a month it started to run rough/jerk only when I stopped at lights. If A/C is running it will act perfectly normal. NO indicator lights have came on. It then started dieing out 1 outta every 5 lights I stopped at. So still being on warrenty by 3 days. I took it in because now it will reproduce for them. They have changed the spark plugs and the valve cover/gasket because there was a small amount of leakage. However, when I tried to take it home 1/2 block from the shop..you guessed it...died at the first stop sign.
It is still in the shop but they are acting clueless.. I have read everything on this website, I have requested they check the Idle control valve, yet they say it is alright. The computer tells them it has a problem but not what it is (thats what they told me). So at this point I am worried.. they have it and I am afraid they are all standing around doing nothing.
Should I also request them to look at the catalatyc converters? or the timing? Or would they look at them on their own.
My chevy I owned previously No problem for me to work on, unfortunatly this is not my cup of tea.. any suggestions?

Thanks a ton
Elli

Update, they called me wanting to know when I last put gas in it. What station etc.. because this started a few weeks ago. They are saying they need to test the gas. I have used the same station (cept traveling out of town) since I bought it. Is this crazy or what?

My friend once put bad gas in his car and the thing wouldnt even accelerate!

with gas zooming to the $4 a gallon region, some no-name stations have been mixing in all kinds of C_ _ _p in the gas. on the East coast they have been mixing in lacquer thinner, waste oil, paint solvent, etc. if it is a reputal gas company, that might not happen.
I did run across the same problem, and it was a clogged front cat converter, there are 2. the AC sets the idle speed up a little, so it burnd off some of the carbon, but offen it quit at every light, when the AC was off.
The engine will put of all sorts of codes when this happpens, plus the plugs will be Black. you need to know exactly what codes it is putting out. The cat runs any where from $75-150 in the after market version. Also make sure the exhaust pipe isn't restricted, or kinked in the middle.
After we changed the front cat, it ran like a new car, no problems at all.

Update #2
They tested the gas, I had some sediment in the bottom and they flushed it out. They found that the fuel pump wasn't keeping pressure and that the connector was faulty. They also disconnected/reconnected battery to reset her. So far she is running great no rough idle/dieing. Except now when I put her into park there is a click sound.
All in all I am just glad to have her back.
Thanks Again
Elli

Glad you got her fixed.