Q: Check engine light and vsa light on in 2009 Honda accord won't accelerate over 20 mph

Hi there. It appears that you have a severe misfire/misfires. The VSC light illuminates when the check engine light is illuminated, by default. When the check engine light flashes, this means that there is what is called a catalyst damaging misfire occurring; this is a bad thing. The catalytic converter can ultimately be damaged and require replacement if your concern is not corrected; this can be very expensive. It sounds like you may have a failing ignition coil(s). There should be stored codes that may direct you to the cylinders where the misfire is occurring and diagnosis can proceed from there. I strongly suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with a (misfire inspection)[https://www.yourmechanic.com/services/engine-is-misfiring-inspection].