Crankshaft position coil for 97 Wrangler

[bopdj]

In the past several months I have been trying to find out why my Wrangler was hard to start. I replaced the fuel pump, did the tune-up thing and it still at times hard to start. I put it on the scanner and no codes come up. My mechanic told me it is the crankshaft position sensor. Before I put another $100.00 into this I would like to know what this part does. I don't have a clue what this is and after looking all over the different web sites I still come up empty. If any one knows if this could be the problem please advise.

[lilgtoguy]

i had my cps goin my 90 wrangler about 2 months ago, and this is what i got from innerauto.com
"The crankshaft position sensor is designed to record the rate at which the crankshaft is spinning. This sensor consists of a toothed metal disk mounted on the crankshaft and a stationary detector that covers a magnetic coil that the current passes through. As the metal teeth move past the coil, its magnetic field is disturbed. This causes a stream of pulses in the current. The computer can calculate the crankshaft's speed from the frequency of the pulses. "