I have a P12000 serial#AT33C80129. TB45 engine will not rev to full rpm until what seems to be shortly after closed loop. I have went through and cleaned entire fuel system, tested vaporizer, throttle pot and electric throttle control. Engine has been tuned up and checked over. Unless I have overlooked something in the fuel system, I am starting to suspect an electrical component. I have also glanced at wiring harness and connectors for anything awry. I have tb45 software, no current codes or any in history. (If it matters,) I have once or twice received an error 87 in the software when trying to learn idle rpm. I'm looking for advice on sensor outputs to observe while the condition is happening, or a problem I have overlooked. I will promptly give more information as needed. Thanks for your help.