code 21 = oxygen sensor or circuit
code 24 = throttle position sensor or circuit
You may want to test both sensors separately, its not hard to do. I'm inclined to believe that it maybe a circuit issue because I seem to recall that they both share the same hot lead from the ECU. Don't quote me on that tho. Test the sensors separately first.
Whoops before I forget, make sure you have a good ground from the engine to the firewall or to the battery before you test any electrical. No point in testing with a bum ground throwing off your readings.
***--- Wrecking Crew member ---***
"I've prolly been around longer than you think"