I have a 2006 Dodge Ram 1500 5.7 V8 Hemi. The past few weeks I noticed my RPM gauge falling below normal then go back up to normal range while sitting at red lights and stop signs. Well the problem got worse and the truck eventually started dying and the check engine light finally came on. I limped the truck to AutoZone where they checked it and said it has a Failed Crank Shaft Sensor. Well we replaced it and it is now even worse then before. Truck will barely crank and the RPM gauge will skyrocket and fall and eventually just die. Any ideas?? Thanks

 

Something I find strange about the whole thing is in the mornings it acts up the worst but in the afternoon most of the time it seems to drive almost normal? Im very confused!

 

What codes did you pull?
Aldo, crank and camshaft sensors work together to time the engine. Fuel, spark etc.
I'd change the camshaft sensor as well.
Check all wiring to and from both sensors for continuity and good connections. Plus no burned or damage wiring as well.
Al.