Mark911 said:Most "stock" engines will pull 20+ at idle if properly tuned and in good condition. If you have a low idle speed or you're at altitude it'll be lower (18 to 20). If your idle is correct and you're not at a significant altitude check your timing or idle mixture. Anything that makes the IAC open more than it should to maintain the proper idle speed will lower the number (including a low battery or other demands on the alternator). If everything looks fine do a compression and cylinder leakdown check. My motor pulls almost 22 inches which I consider good. (I'm assuming your gauge is good).
gobble said:We tested this afternoon with a real vacuum gauge an saw 19, 19.5 at idle at the same time my autometer gauge read 18. My numbers were the same as the other NSX that stopped over. We then tried to check the timing, but it appears impossible with all the new CTSC pulleys blocking the view. Anyone have any tricks for checking timing with a CTSC installed?