Vacuum gauge reads 20>21 but needle has needle shake and it is why I say 20 or 21. It has needle shake like scenario #3 on the link below except that the numbers are 20>21. Shakes so fast it is very blurry.
http://www.secondchancegarage.com/public/186.cfm
The explanation of such rapid needle shake as that on scenario #3 is valve overlap, intake and exhaust momentarily open at the same time. A car with such needle shake would be a high performance engine with high lift, long duration and large over lap. I don't think that is a description of a stock 2.5.
None of the 15 scenarios come close to my results -- except #3.
Err I can't remember but acceleration drops the needle to zero or close proximity and up to @25 on deceleration.
http://www.secondchancegarage.com/public/186.cfm
The explanation of such rapid needle shake as that on scenario #3 is valve overlap, intake and exhaust momentarily open at the same time. A car with such needle shake would be a high performance engine with high lift, long duration and large over lap. I don't think that is a description of a stock 2.5.
None of the 15 scenarios come close to my results -- except #3.
Err I can't remember but acceleration drops the needle to zero or close proximity and up to @25 on deceleration.