Well from what your saying, "too much fuel" Could be due to oxygen sensor, Un-metered air getting into the throttle body (usually due broken / cracked / disconnected vacuum hoses), really poor fuel pressure, a MAP sensor problem.
It would help if you gave the code #
Check your Vacuum routing on the underside of your hood and check all your vacuum lines
One thing you may want to try to do is run some sea-foam in your throttle body.
I feel like we should advertise that stuff on here, because were always recommending it. hehe
1. INSPECT IAC VALVE OPERATION
(a) Initial conditions:
• Engine at normal operating temperature
• Idle speed set correctly
• Transmission in neutral position
(b) Using SST, connect terminals TE1 and E1 of the data
link connector 1.
(the SST Is a fancy connector. You can just use a stripped wire to jump the Te1 and E1 connectors)
(c) Maintain engine speed in the range between 900 –
1,300 rpm for 5 seconds. Check that it returns to idle
If the engine speed operation is not as specified,
check the IAC valve, wiring and ECM.
2. INSPECT IAC VALVE RESISTANCE
(a) Disconnect the IAC valve connector.
(b) Using an ohmmeter, measure the resistance between
terminal + B and other terminals (ISCC, ISCO).
If resistance is not as specified, replace the IAC valve.
(c) Reconnect the IAC valve connector.
hope those images and info helped ya!