In high dust areas, problems with the EGR system are common. The filter for the EGR solenoid may plug and cause the EGR to activate when it should not; this can cause the engine to stall. The dirty filter should be replaced to correct this concern.Google+
Car Problem Reports
Lincoln Town Car Problems With EGR System are Common in High Dust Areas
Lincoln Town Car Problem
Average Mileage: 159,502 mi (135,000 mi - 184,005 mi)
Visitor, 1994 Lincoln Town Car, 184,005 mi
Engine misses, hesitates, backfires, and has poor fuel economy; I have replaced all spark plugs, wires, and coils. along with fuel filter and air filter. I have also checked for vacuum leaks.
replaced EGR valve, not even a year later check engine came on again and it was the egr again!