Having emission problems co is drifting between 0.60 and 1.0 hcs are from 120 to 160 no codes in memory,live data looks ok except one thing the atmospheric pressure is at 1500 and map at idle is at 560,map volts ok 4.5v with ign on 1.2v at idle.Had another 306 the same in checked live data atmospheric pressure 1005 and map at idle 340,any ideas. (swapped over map sensors still same)