550 engine light on says go slow?

Go slow light flashing isn't that bad...when its lit solid its time to pull over!

I believe the "Go slow" is a measurement of Cat temperature... as opposed to the "check engine" which could be any old sensor. This should definately be checked out by the dealer...sooner rather than later. No way to diagnose this over the internet, you need the computer hookup to tell exactly what is wrong,...could be little or lots...Good luck!

 

The O2 sensor probably failed. I had a lot of problems w/ mine failing on my old 550. Can you exceed 3k rpms? ( I think that is the limit in limp mode? )

Regards,
Chris

 

The slow down light is triggered by the thermocouples and attached control units, not the O2 sensors.