I wanted to add a little closure to this, as I seem to have finally sorted out my hesitation under load and poor idling issue. Of course it was something simple. After throwing a bunch of parts at it with no success, I spent hours and hours searching stangnet and coral tech forums for solutions. I used a vacuum pump and checked every Vac line on the engine. Found a leak in the T connection to my Vacuum guage, I figured, problem solved. car ran better, but still hesitated. ](*,) I got a SNEEC IV Computer interface device off ebay for short money and managed to get it running on my laptop. Works great and I can see what the eec sees from the sensors. It showed me my 02 sensors were not acting in concert or switching as well as they should be. Turns out my o2 harness had gotten melted on the exhaust once apon a time and the patch job wasn't very good. Ireplaced the harness and the code 44 went away. So much for my theory of my heads being blocked up. The car ran better, but still hesitated. I wanted to cry. ](*,) I tried a bunch of other things with no success. I decided to switch out the Idle air control solenoid with a spare one I had (after all this I have a spare of just about everything [smilie=icon_cheesygrin.gif] ) I took them both apart to make sure they both worked, and low and behold, the one I was using on the car was missing the rubber oring that keeps unmetered air from entering the IAC. You can see it on the right Here you can see the oring on the solenoid. I had bought a used Ford Motorsport 65mm throttlebody off eBay and either it didn't have the oring in it when I got it, Or I took it off when I was cleaning it and forgot to put it back on. Basically a 2 cent oring was driving me nuts. If your car is hesitating at low RPM under load, check for unmeterd air getting in somewhere. Hope this helps someone else. Im still trying to figure out why my left o2 sensor seems to be not as responsive the right one. but for now, problem solved.
