it rained really hard last night and this morning i went out to the jeep (87 XJ) and started it up and it reved to 2,000rpm and would not go down so i shut it off and unplugged and replugged the tps and it started and ran right. then i shut it off and restarted it and it revved up to 2,000rpm again what is wrong?. (I have hood vents)