My 92 dakota,3.9 is having a few issues...every once in a while while accelatering it bucks a couple time then goes on,never know when its gonna do it,and when it sits while the trans is hard shifinting out of first to second.(automatic)but is fine after that.....it idles perfect,fires right up and runs great...the codes are...12,15 and 55....any ideas

 

Have you reset your PCM?
By "bucking" you mean that it gives and goes, gives and goes?

 

Here is info on code 15:

http://www.allpar.com/fix/codes/faults/code15.html

 

the bucking was one of the wires going to the coil shorting on the manifold..motor runs perfect..the transmission whines and is hard shifting out of first when cold,but changes fine from second on even to overdrive,after it warm is does alot better...I cleared the codes and drove about 35 miles,stopping a couple places....rechecked the codes and got 12 and 55,no other codes.....

 

Glad you got it fixed. When did you last change your tranny fluid and filter?

 

just bought the truck from the original owner,the original 3.9 croaked so he put in a motor with 71000 miles,runs perfect,not sure when or if he changed the fluid,gonna do it today and see what happens.the truck has 155000 mile on it.I had a '92 full size with a 318,changed the fluid and the trans died a week later.....