I have a 99 SL1 that in the last two weeks while at work will try to start the engine cranks but it just wont turn over after about an hour it fires right up

......Any thoughts

Sounds like the crank position sensor ( CPS ) reasonably priced and not too difficult to replace. When replacing, make sure it seats fully and the retaining bolt is used.

I second that.... sounds like the CPS alright.

http://i202.photobucket.com/albums/aa293/richpin06a/Crankshaftpositionsensor.jpg

"crank but won't start". you say it will not "turn over". ?

It has full power when I try to start it it just wont turn over

By turning over do you mean the the starter is spinning the engine over but it is not firing or starting.If that is the case the problem could be a bad CPS like yaz and i have stated.