Pete,

<<< I make Ian's readings equating to about 19 - 20 "hg which I make quite reasonable. Do not understand the "two different ends of the scale". Mind you as soon as I hit the "send" button it might come to me! >>>

The clue is the use of the word “absolute” in Manifold Absolute Pressure. This could take the thread way off topic though. There could be something in the archives as this was discussed in detail years ago, back when such discussions were common place. Should be loads of info on google as well.

A correct MAP at idle for that car should be approx 300Mbar.

HTH

Alan