The EGR solenoid regulates small amounts of exhaust gas.The EGR which means exhausts gas recirculation. You have a EGR valve that the exhaust gas run through ,is controled by the EGR solenoid allowing the precise control of EGR flow. Unless he ran a diagnostic check on your car, you might want to consider having one done. If you put a few dollars more of what a check would run you you can buy one of the dtc readers and it will give you a code which the better the dtc reader the more precise of problem with out doing a check its possible your cars not going into overdrive could be your evap valve, which that was what my problem was with my vehicle not wanting to go into passing gear. A good reference manual of your year vehicle that you can get at most parts stores can keep you from being taken for a ride.