99 Ford Windstar, pinging
Here is the problem I am having. I have a 99 Windstar with the 3.8, it is pinging like you would not believe. Any kind of incline, or when it gets up around 2600 rpm. I have had new plugs, wires, intake gasket(was installed after plugs and wires), fuel filter and injector service. I was told the intake gasket was leaking and it caused it to ping. Well, it is still doing it. It will go away if you use 93 octane gas and use stp fuel treatment. Could it be the egr? It also has a rough idle after to come to a stop in drive. It has lost a couple of mpg but nothing bad. And no check engine light. Any help?