Checking Engine RPM
Another overlooked test is to check engine RPM.
Setting high and low idle by ear is not an accurate way to do it.
One method is to use a Vibra‐Tach.
Another is to use a Photo Tach.
The key is that RPM, both Low and High is properly set.
When working with multiple cylinder engines, sometime
the performance problem may be related to only one
cylinder.
To determine which cylinder is at fault, perform a Cylinder
Cancel Test