Turns over wont start does not seem to be pulling vacuum from intake lagging at first

A concern where the engine will crank but not start indicates a problem with one or more of a few areas. First, you could have a fuel delivery problem. You could have a lack of ignition spark. Engine timing could be disrupted. Engine compression could be compromised. Proper air intake to the engine could be interrupted or too plentiful. Testing hands on is required to find out what is happening. All of it is impossible to figure without testing the vehicle hands on.