While trying to sort out a bad stumble and poor idle problem last month, I ended up swapping a -561 white label ECU for a -951 ECU from a pick-and-pull car. The car seemed to run better with the -951 than the original ECU-- more pick-up and an improved idle. The car ended up with a different AMM and a replaced 02 sensor to correct the poor running.

Ever since the bad running my wife would rather not drive it anymore, so I am using it daily. I have noted that on start-up the -951 runs a very high idle for a few seconds and then drops to normal. My -561 never did that-- is there a difference in that regard between the two, or was there something abnormal about my -561?

Just curious...