As you state readings are similar to mine. I also have 185+ PSI on compression test. I would welcome someone elses test results for clarity. Your fluxtuating vacuum may well be a small leak. Does it idle smooth or not? Poor ignition could also be the cause.

For the synchronisation test I was getting a much higher vacuum (more like 16in)on each throttle body but this was just from the wild deflection you get without a check valve. Again would welcome some more comments after you have done the trick with the check valve.

Best of luck

Ian

Well I may have anwered my own question... saw way below in first discussion of throttle balancing that Ian got something like 80kPa which is 9 in Hg. Also saw from throttle balancing instructions that in their example the average for each throttle was like 9 inHg (300 mBar). So as someone explained on the E28 board, this engine doesn't pull as much vacuum because of the cam overlap. Sound right??

Put a vacuum gauge on a "T" fitting between manifold and fuel press reg (so pressure reg still hooked up to vacuum line)/ Get a reading at warm idle of 6-10 inHg, which afaik is quite low??? expecting 15-22? needle fluctuates with idle speed +- 2-3 inHG. So maybe I have a vacuum leak somewhere? getting a check valve later so I can check each cylinder. Any comments appreciated! (note - compression good at 190 on all cylinders, valves just adjusted 2 days ago).