I have an 89 GT 5.0. Not my daily driver. Lately I've noticed that randomly at stop lights my rpms shoot up to 1500-2500 and just sit there. when i put it in first and start to move the rpms drop. As soon as I hold the clutch in they shoot back up. I will let the car sit idle for 5 mins and the rpms will slowly drop back down to 800ish. The car doesnt always do this but it does randomly. Usually if ive been driving for 15 mins. I gave a good friend of mine that is a mechanic. He says its spitting out code "44"? Not sure what that code is... Regardless he says its doing that because I removed my cats and the sensors are acting up. Earlier this summer I had a hole in the wall shop install my flowmasters. They did completely remove my cats and install flowmasters. The exhaust is dumped, (turned down) right after the flowmasters about half way down the car. Do you think my lack of cats is causing this? My guess was its the throttle positioning sensor acting up. He disagrees because he isnt getting a code for it.