I just had my head gaskets replaced and instaled arp bolts. Had as new water pump instaled to. Before head job the truck would go into limp mode every time I got on it hard. Sense I got it out of the shop I've tested it out on the highway. Got up to 125 mph . Then it jumped into limp mode again. What can I do to stop the limp mode issue? Any help would be great.

 

may be transmission.

what code(s) does it have

 

I havent been able to get a code on it.

 

thats odd, should have definitely been at least one code if it went into limp mode. what about the code history, anything in there?