I have an 08 420 that runs perfect when it is cold but after it warms up it acts like it has a rev limiter. It will still idle, but will not rev up. It did this occasionally at first, but has gotten to the point where it does it every time. The Radiator is clean and water flows great. I have tried removing the thermostat, I have replace the ECM…when it cools down it runs great again.
Won’t run when hot
I have an 08 420 that runs perfect when it is cold but after it warms up it acts like it has a rev limiter. It will still idle, but will not rev up. It did this occasionally at first, but has gotten to the point where it does it every time. The Radiator is clean and water flows great. I have tried removing the thermostat, I have replace the ECM…when it cools down it runs great again.
