My '98 Lumina is hard to start. The starter needs to turn several times before the engine will start, but once it's running, it's fine. I've decided, from reading some of the other posts here, that the first step in the process of elimination would be to replace the crankshaft sensor. It appears to be about a $20-30 part and would like to make an attempt to replace it myself. While I'm not totally auto-illiterate, my knowledge of "todays" cars is limited, as is my patience when things don't go as planned

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Can anyone give me the basics on what's involved in replacing it (including it's location) and, if available, what the book time is in case I want to have a shop do it?
Thanks, Jim