92 Taurus Wagon - Help

"engine diesals" (sic) is where the engine continues to run (badly) for a little while after the engine is shut off. If your engine is surging or hunting for a steady idle speed in Park, the most likely problem is a dirty/worn idle control valve, a shiny metal cylinder bolted to the throttle body. See:

Do fuel injected engines diesel?

Just about all diesels ARE fuel injected, & have been for a long time...

Rob

ROB, get a brain.

He was asking if fuel injected gasoline engines diesel.

The answer to that is yes they do. Especially if they have leaking injectors they can diesel.. It isnt common for "dieseling" to occur in a fuel injected gasoline engine, but I have seen it happen, and it was usually due to extreme leakage from atleast 2-3 injectors..

Ford Tech

I dont think what your car is doing would be accurately described as dieseling.. Dieseling only happens when you turn the engine off, and it continues to run.

I think what you are describing is called "Hunting, Surging, or Rolling Idle". This is where the RPM's on your engine are NOT stable at idle, and go up and down as if they were on the ocean. Hence the term "Rolling" like waves...

I am with Sharon Cooke on the diagnosis here as well.. Check the IAC valve.. Possibly just replace it..

Ford Tech

Thanks.