2004 Pontiac Grand Am

My Granddaughter has a Pontiac Grand Am and this past March she had to have a motor put in her car. It ran real well till this past Monday. April 7th. My husband checked all the fuses and had to replace a module. It ran all evening and the next morning it wouldn't start again. So worked on it checked all the codes they were all right. Put a different battery in it it started. So she bought a new on. It ran again till the next morning again now it turns over and won't start. We were told it could be a crank shaft sensor is this what it could be?
April 10, 2014.

Any vehicle if it cranks good but won't start, have a helper crank it while you visually check for spark at the sparks plugs. If you have spark everywhere, check fuel pressure.

Also check fuel injector pulse, without rpm signal, no injector pulse. The rpm signal comes from crank sensor. Depending on your problem, the crank sensor could be the issue?

Apr 10, 2014.