Lope with Dr. Performance box

[307diesel]

Does anyone know why some trucks lope violently with a Dr. Performance pressure box? I had this box on my 06 a few years ago and just sold it to a guy, he put it on his 06 and it lopes violently no matter the setting on the switch. On my truck it had no ill effects. My suspicion is that the ecm in his truck reacts differently to the pressure box than the one in my truck. Hopefully this can be confirmed or found that it's a sensor or something not right. Thanks for any insight.

 

[Striper]

I bought one used a few years ago. I had some issues with mine sometimes. I sent it back twice to get checked and they said it was fine. The third time they acknowledged there was a problem in the harness. Ended up getting a new box and all is good now.