1995 Regal GS starting problems

I have a 1995 Regal GS and have intermittent starting problems. It seems that after the car has been driven for a little bit (45 minute drive home from work) and I stop it for a while (30-45 min, going to the store, etc.) I come back out and it won't start. It cranks like it wants to start, but the engine just won't turn over. Sometimes the Check Engine light comes on, sometimes not. I had a mechanic look it over and there were two trouble codes referencing the ICM. That was replaced, yet the problem remains. The mechanic has had the car for four days and has not yet duplicated the problem (happens to me at least once a day!) I've read over some posts on this forum and most likely believe it to be a faulty Crankshaft Pos. Sensor. However, since the car has not given any new codes out, the mechanic is hesitant to just start replacing stuff. My question is, how difficult is it to install a new CPS by yourself (im not a mechanic, but have a decent understanding of cars, ie, plugs and wires, fuel filter, tranny fluid and filter replacement, etc.) And I was wondering is this something I can attempt myself, or would I be better off paying someone to replace it for me. Thanks for your help!

do a search on this forum for testing the CPS with ice water before replacing it.

i can't remeber if you have the reluctor ring or the pulley mounted ring, ether way i doubt its to hard.