For over ten years now the auto engines are computer controlled. The
computer determines the air to fuel ratio.
Installing a filter with better flow, such as the K&N could potentially
increase the air available to the engine.

I have 97 Ford Explorer with 104K miles on it.  When slowing on the freeway,
I sometimes hear the gears whir and get no response then when attempting to
accelerate.  I can put it into neutral and then pump the gas pedal and then
put it back into drive and it reengages.  Tonight I ...

I put in Jim's name in hopes of getting his attention. It appears to me that
Jim is a professional Ford mechanic.
For three years now I've been dealing with a bad idle. When sitting at a red
light; the rpm's are on the low side, the engine sort of vibrates, enough