I had this problem with in the several months ago after i changed out my plugs and wires. Every time i plug in the throttle position sensor the car will only go up to 3000 rpm's and cut off back to the idle, but if i leave the TPS unplugged it will do just fine, but the engine will lack a lot of power. By the way i but on a new TPS and the problem is still there. I was wondering if anyone has encountered this problem thanks for the input.