when there is a load on the truck lets say a big gooseneck trailer. as your going down the road it is running fine then the check engine light comes on and it powers down to less than 2000 rpms, and will not get above that until you pull over and turn the engine off and restart the vehicle. i hooked it up to my determinator and all it said was it had a leak in the fuel system. this truck runs very good even while its powered down it does rattle miss or anything please help.
