Check engine light when towing and speed > 60mph
The check engine indicator on my 2003 Suburban comes on periodically for a few
seconds. This happens when I am towing a camper. I have to first exceed 60mph,
then slow down. When the engine is not under as much load, the check engine light
blinks on and off until it is under load again. In other words, if I am accelerating or
maintaining my speed, nothing happens. If I am coasting, the check engine indicator
blinks on and off.
This does not happen when I drive at or below 55 mph. It also does not happen when I
am not towing the camper and driving at any speed.