P1518 and P1520 are both indicating problems with the IMRC or Intake Manifold Runner Control system. See link below for a little more information on it. The IMRC actuator is bolt on top of the right side valve cover next to the radiator. Would check to make sure the electrical connector to it is even pluged in to start with to set both of those codes. In the first pic of this link you can just see the IMRC actuator at left edge and connector too.
Is the purge solenoid valve connector broken or just wire to it?? Lot of problems with broken wire due to harness being to tight. Purge valve is located on the rubber boot between air cleaner and engine. Check both of these links to both location and TSB for harness repair.
Flashing CEL means that a severe engine missfire is being detected that could damage your catalytic converter and cost you a lot of $$$$ to replace. Should also have set a code with P0300-P0306 code.