I changed the timing belt on my '88 Escort about a month ago and ever since my engine vacuum has been lower than normal. Before I changed the belt the engine vacuum would run about 20-21 inches of vacuum at idle and 24-25 inches of vacuum during deceleration. Since changing the timing belt the engine vacuum at idle is running 15-19 inces of vacuum while idleing and about the same during deceleration. The vacuum goes up when the temperature goes up??? I pulled the codes and got code 22 - MAP sensor or BP sensor signal voltage out of specification (engine off) or not at normal vacuum levels (engine running). I've rechecked my work on the timing over and over, everything is perfect. I've checked all the vacuum lines several times and replaced one that was in question, but didn't do any good. I've tried a different MAP sensor on it from my other '88 and nothing changed. The vacuum is steady and the car is running good. The worst part is it's caused my fuel mileage to drop anywhere from 2-6 MPG on every tank since I change the belt. Does anyone have any idea what could be the cause of code #22?