thanks for all the replys. I have used the check list and fixed my idle problem.it was very helpfull.when i bought the car it would not even start or run.so hats off to you for your check list!far as i known the computer and harness is out of a 1991 5.0 stang.the computer is A9P.I have put a new iac,tps,plugs,cap and rotor on.i have pulled the codes and fixed what was on there then erased them.i have not checked them again have not had the time to.the car will stall out at a 1000 rpm or lower.it is like you cut the ignition off.i checked the msd box and wiring everything was ok.the car runs to good down the road to have a ignition problem.the guy who wired the car cut out any wires he did not want to use.so little by little i check and move on.i just thought that this was a good place to start.thanks once again!