Hi Randy,

Thanks for the reply. I do have the 516 pink labeled ECU. The car will start and run fine. It idles high though and won't maintain a constant idle when in gear or lights on. It idles at 1000 rpm and will drop to 800 when in Drive. Either while driving or stationary the engine cannot be reved past 2000 rpm. It falters then immediately picks up again and runs. If you keep the throttle open past 2000 it falters, the revs drop and then pick up again then falters once more. This will continue at an even repetion rate. I've checked out the AMM on two other cars and it works fine. I replaced the tank pump and filter. ( Found out that the tank pump wasn't working.) Also replaced the main fuel pump, fuel pump relay, main fuel filter, fuel pressure regulator, throttle position switch, cleaned the throttle body, tried another idle air control valve, cleaned the fuel injectors, removed the hot air induction and blanked off the port in the airbox, cleaned and checked the fuses and fuse connections, and cleaned all of the ground connections in the engine compartment and the problem still exists. The onset of this problem was intermittant for a couple of weeks and now is constant. The odd time the engine will rev freely but within 1/2 mile of driving the hesitation returns. The car will maintain only 40 MPH or 60 KPH with very light constant throttle. Brian.