hey. My girlfriend just bought a 99 tiburon. She's having a little trouble with it I'm not sure what's wrong. The check engine light is on. here's the problem when she starts it up in the morning and pulls away if you step on the gas hard at all the car will cut out and stall if you don't let off the gas. once the car reaches operating temp it runs great. expection on the hills the car looses power and dies back. what could this be.. I was thinking of an oxygen sensor? would that cause this type of problem
it's a 1999 tiburon 2.0auto.
new plugs, ,wires, and coils

I have tryed to reply to the other topic but it won't let me? here is the code i'm getting
P0134 02 Sensor Circuit No Activity Detected (Bank I Sensor 1)