can a faulty crankshaft position sensor cuase RPM guage to malfunction

Hello, your crankshaft position sensor may set a code even, but is not likely the cause of your prolonged starting concern. It's hard to know if it's affecting the tachometer; possibly so. Testing with diagnostic equipment and checking circuits of related components is needed. For the starting issue - Diesel or gasoline engine? You can get some local assistance at a RepairPal Certified shop near you: https://repairpal.com/auto-repair-near-me Click the link or call us at 877-913-1554. We'll gladly find you a certified RepairPal shop in your area.