mackmike01

I recently purchased a 2005 mack granite cv713 dump truck. 

Problem one: I only get a check engine when it idles for more then 10 mins and they are all low/shorted/open circuit codes. 

Problem 2: the truck pulls a load with great power until 4th and especially when I kick it in high range. The truck will pull good and then acts like I reduced to half throttle. No smoke or anything. Then I will hold it at the floor and it will kick in to full power again.  It goes on and off when it wants. Might stay full power. Might not, until I get a load off it(go down hill or flat)