I have a '94 Ranger RWD with a 4.0 and it ran like crap the other day so I read the code, 159. After doing the easy stuff, that didn't work, I removed the ECM and replaced 3 blown capacitors, reinstalled the ECM and it runs great. Got the caps @ Moser Electronics. 2 are 47u and 1 is 10u. The hardest part is getting to the ECM. I worked from the top after removing the cruise control can, 2 ground wires and the main connector into the interior. The bottom nut on the ECM cover wasn't too hard with a short 10mm socket, a u joint and a 6" extension on a 1/4" drive ratchet. Putting it back I dropped the nut and there is stays.

 

You get an Attaboy for not giving up & diving right in, so to speak.

I read the 159 code as MAF sensor out of self test range. So what do you suppose caused the ECM caps to self destruct??? You haven't been messing around with internet suggestions about installing resistors to change the MAF circuit readings it sends to the ECM, have you????