Hi i have a 2001 Dodge Dakota sport 4x4 with a 3.9 liter v6 with 199,000 miles on it . I first had a missfire in cylinder number 3 so I changed the plugs but didn't have the money to do the wires yet then I got a random missfire plus a missfire in Cylinder number 1 so I changed the wires and the I got a Cylinder number one missfire so I then replaced cap and rotor still same cylinder missfire so I changed the fuel injector still same missfire did a compression test of all cylinders no varience does anyone have a idea what else this could. Also I get a code for p1494 leak detection pump switch malfunction also sometimes it will die in reverse or forward if you let of the gas quickly any thoughts

 

How old is the crank sensor? Bolts to the block behind the passenger cylinder head. Get MOPAR SENSOR ONLY. PAY THE DEALER RIPOFF FEE. Been there, done that, have the teeshirt, and finally paid up after 2 box store sensors.

The 3.9 PCM gets very pissed off if the crank sensor gets more than 5 degrees off.

 

what problem was this supposed to fix the misfire or the p1494 code ?

 

you did say 2001 right??? It's a problem within the computer itself. Had that and chased it in my 01 Durango. some solder joints within that work loose. Had to send my computer in twice to get it right.
difference was mine was cyl #6..... but same problem, misfire I couldn't find within the engine, fuel system or ignition system, replaced a bunch of parts and did a lot of testing to chase down...
send computer off for repair.

 

Dodge had a problem with cylinder heads with more than 70k miles on the 3.9 , 5.2 and the 5.9L. Those were from 1996 thru 2006.

 

what kind of problem, with the heads? sunk seats, cracks, or something else?

 

cracking. lots of cracking.

 

Ya it's a 2001 the pcm has been replaced a few years ago. But a buddy of mine had said it might be the intake manifold gasket and since I was planning on doing the valve cover gaskets I went ahead and did the intake manifold gasket too . Now here is one other thing if it's been sitting several hours when you go to start it up and you turn the key it doesn't fire up right away a few cranks then fires but today after sitting for several hours while doing the gaskets for intake and valve covers it fired right up also did do the crank position sensor as well check engine light came on

 

where did you send it too and how much did it cost ?