Hello.

My 2006 Mustang had its PCM replaced. Instead of various codes coming up, now the only code showing (after the Check Engine light appeared two days after the PCM was installed) is the P0403 EGR.

However the EGR was replaced two months priors to the PCM being replaced along with the spark plugs and its cable box.

Secondary DTCs are appearing as well: Evaporative Emission System: P0443 (Purge Control Valve Circuit) and P0456 (Leak Detected (very small leak)).

Any ideas? Gas mileage is still really bad: about 10 to 12 MPG (a lot of stop and go traffic).

Instrument cluster needs replacing: RPM and gas gauge do not work.