Idle's high (2000rpm) at start up. Will begin, at ~800 rpm, but as it warms, will climb to around 2000rpm. Won't correct until ignition turned "on and off" several times. I checked the tpi voltage. Recently took to dealer, they claimed noisy fuel pump to be cause. Changed fuel pump, no change. Any ideas? Has had codes P0306, P0122, P01122, P1406, P1380. The dealer attributed these codes to the cat. conv. being bad. New cat., better performance, but still high idle problem.

A P0306 code means that the the car's (http://www.obd-codes.com/p0306#) computer has detected that one of the engine's (http://www.obd-codes.com/p0306#) cylinders is not firing properly.
A P0122 code means that the the car's (http://www.obd-codes.com/p0122#) computer has detected that the TPS (throttle position sensor) is reporting too low a voltage. On some vehicles (http://www.obd-codes.com/p0122#) that lower limit is 0.17 - 0.20 volts (V).
If the signal value is less than .17V then the PCM sets this code. Could be an open or a short to ground in the signal circuit. Or you may have lost the 5Volt reference voltage.

also, i'd recommend to do the drive cycle, to fully diagnose your powertrain, before reading codes

A complete driving cycle will perform diagnostics on all monitored systems and can usually be completed in less than fifteen minutes.
Performing a GM OBD-II Driving cycle:

Cold Start In order to be classified as a cold start the engine coolant temperature must be below 122°F (50°C) and within 11°F (6°C) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.
Idle The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.
Accelerate Turn off the air conditioner and all the other loads and apply half throttle until 55mph (88km/hr) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
Hold Steady Speed Hold a steady speed of 55mph (88km/hr) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
Decelerate Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 20 mph (32km/hr). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
Accelerate Accelerate at 3/4 throttle until 55-60mph (88-96 km/hr). This will perform the same diagnostics as in step 3.
Hold Steady Speed Hold a steady speed of 55mph (88km/hr) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
Decelerate This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.