Car started fine a couple days ago. On the way home from work, the check engine light came on then went of a few times. Now it cranks and cranks but will not turn over. It has gas, oil, no blocking of airflow. Any ideas?

you'll have to start by checking fuel pressure and ignition spark.
what year,make,model and engin size?

do you know what the fuel pressure is, just getting fuel to the engin doesn't mean it will run, it has to have at least 50 spi to fire injector.
it could be a lot things causing the no start, but you have to rule out thinks one at a time to be sure of just what is causing problem and save money.

you can rent a guage fron advanced auto or pep boys and check it yourself, they donn't charge much, may not even charge you if your going to buy parts from them??

James,

You stated that the check engine light came on and then went off a few times. Well, the first thing is, you shouldn’t think that because the light went off that the problem is fixed. It isn’t. The next thing is there is connection between the light coming on and the car not starting now. The light came on because that’s what it’s designed to do. It’s telling you that there is at least one stored error in the computer. Do a scan and post the error code number or numbers. That information will enable us to furnish you detailed repair information. Yes the problem could be a timing issue. Post the results of a compression test and we’ll tell you if it’s a timing issue.

Here's just a few more possibilities to rule out:

Fuel pressure and volume issue
Blown fuses, circuit breakers, or fusible links
Crankshaft position sensor issue
Fuel injectors not firing issue
Primary (and or) secondary spark (ignition) issue
Excessive exhaust back pressure issue
Serious loss of engine vacuum
Failed "PCM" (aka computer)