The 2008 Chevy Uplander is going to have it's crankshaft position sensor located on the lower right hand of the engine block and near the relays. You're not going to need to remove any parts in order to access it but You might have an easier time finding it if You're underneath the vehicle instead of looking under the hood. If You need a replacement sensor they will cost between $20 and $60 depending on if You want an OEM part or an aftermarket sensor. If You want to have a pro install Your new senor the cost will be between $160 and $260.