One problem related to gas recirculation valve (egr valve) has been reported for the 1998 Ford Mustang. The most recently reported issues are listed below.
After service of my 4. 6 Mustang gt, my car began missing and I had the diagnostic complete it reported a misfire on plug 7 & 8, so I had the plugs replaced. During the replacement, I saw coolant under both the 7 & 8 plug. The misfire continues, and I took it to the dealer they told me the intake manifold had failed and that there is no remedy for the consumer even though Ford is aware of the problem and has a kit to sell to the consumer for 900+ dollars. Fleet cars taxi, crown vic's used by sheriff departments were cleared for replacement, but no the consumer civilian. What sense does that make? if the engineering is bad, and it is, the replacement should be for all owners of the 4. 6 liter engine. How is the segregation of fleet cars from personal use vehicles legal in this country? everyone who owns these defective vehicles should have a replacement made available regardless of when the failure occurred, and what other damage can I expect to find? will this have a daisy chain of failures due to the bad design? I understand the cost to replace will be $1,200. 00 + with the dealership estimate parts and labor.