My check engine light comes on and the RPM tach drops to zero. This doesn't always happen. But it's starting to happen more often than not. I've owned this truck since 1999 and this is the third time this has happened. The dealer fixed it the first two times. Now I'm out of warranty. They replaced the crank sensor both times. Can anybody tell me what is involved in changing this sensor? My truck is a 2000 Quad cab 4x4 2500 134,000 miles.