Originally Posted By: c3po
I got out there today and I hooked up the vacuum gauge and it was reading between 19 inches and 20 inches, and I backed off to about 19 inches.
I decided to check my intake manifold bolts, and a couple of them were loose, so I tightened them. The car ran pretty good, it was 40 degrees outside.
I think Demarpaint was right in that carburetors like 55 degrees or better outside, it ran great when it was 72 degrees last weekend.
I still think there may be a slight vacuum leak, or maybe I need to change my fuel filter, when the car is totally warmed up and I put it in reverse, its like the engine is shaking a little bit.
If I had between 19 and 20 inches of vacuum what does this say about the condition of the motor, or maybe this means nothing.
The only other thought is that I could spray carb cleaner around the base gasket of the carb where it meets the intake manifold, or spray it around the vacuum caps and the vacuum lines.
Why spray carb cleaner, do you suspect vacuum leaks now? The gauge will tell you if you have a vacuum leak, if you have a leak don't adjust the carb using the vacuum gauge it would be pointless. Locate and repair the leak first. Was the needle steady or wobbling? There are tables in the shop manual that will tell you what the readings mean, use them to determine if you have any problems, or a good vacuum leak free engine.
Edit: Keep in mind if the needle is fluctuating up and down by 1 lb from lets say 19-20 lbs. it could indicate an ignition problem. If so check the spark plugs, spark plug gap, coil, cap rotor, wires. Fluctuations of 3 to 4 inches could indicate that the valves are sticking. 15-22 or so inches of vacuum is good as long as the needle is steady.
