Hi I live in the UK and have a Dodge b2500 van 3.9v6. I have changed all of the usual, spark plugs, rota arm dis cap, wires and recently the van started to make loud banging/backfiring sounds the loss of power and shut down. sometimes would start up straight away other times just cranks.
I have had the Crankshaft positioning sensor changed. The garage (not a very good one) says timing chain needs changing? Any advice? it seems to run fine until under strain.

 

Backfiring only happens under 3 conditions, lean fuel mixture (fuel pump or pick up coil), bad valve timing (stretched timing chain), bad ignition timing (crank sensor).

 

Thaks Alloro, can always rely on you for a direct answer. Excuse my stupidity just to check Pick up Coil? ive not heard this term before?

 

Here are a few options for the pickup coil for your engine:

http://www.rockauto.com/catalog/x,ca...,parttype,7176

 

It's in the distributor under the rotor. It's also sometimes referred to as the cam sensor.