Hello, I have a 2007 Cadillac CTS 3.6. The engine seized up, so I replaced it with a 2006 engine. My problem is that it cranks, but will not start. If I try starting it a lot it starts to smell like gas. I tested the spark, and it gets spark, but it’s dull, and slow. Also it kinda sounds like it’s cranking slower than usual. Do you think this could be the crankshaft sensor, and should I put the 07 Sensor in the 06?