yes, check for codes. Since you replaced the sensors, I would check your wiring to the sensors. Animals have been known to get in there and chew things up. To have both of these on at the same time is suspect. your MAF or Ignition coil wiring might be affected also. that could account for the running bad at 55mph. A scanner should show misfire or MAF codes if that is the case also.
the shaking could also be a wheel or drive train issue so be careful!