I bought a boom lift with the Ford LRG-425I engine in it for a project, the issue it has is the engine surges when started for a couple minutes then dies, when you first turn on the key the throttle plate cycles open close very fast then stops when it starts then it starts cycling the throttle butterfly again causing the surging, I replaced the throttle body because it had a missing tooth from the rapid cycling and the butterfly became stuck this unit also has in it the throttle position sensor but didn't help I pined the harnesses from sensors back to the ECM everything was good also checked the grounds. I think it's the ECM. Is it normal for the ECM to rapidly cycle the bitterly on the self test? I could understand that it could do a cycle to check parameters but what it's doing is odd. What do you guys think it might be. Thanks Bob