A simple cone filter and a MAF adapter will not get you any gains. Replacing the stock Accordion tube will get you maybe 2-3 HP and one or one and a half MPG, but only while moving and in cold weather. Putting a cold air extension like one from Nautilus Performance Group will maintain the above gains while standing still, increasing available torque for take off.
There are turbo's and super chargers available for the cougar as well. By dropping in a 3 liter Duratec V6 and a Vortech Super charger, I've seen people pull low 400's, but the cougar is not heavy enough to put all that on the ground.
In the valley under the upper intake.
The 1997 Mercury Cougar 4.6 liter engine intake manifold torque sequence should begin at each end of the manifold. Keep moving towards the center and alternating from and to end.
On a 2001 Mercury Cougar : The Mass Air Flow Sensor is between the engine air filter and the big engine air intake tube
The IACV on a '99 Mercury Cougar V6 is on the top right of the Upper intake manifold, there is a hose leading from the intake tubing to the IACV. On the I4 Zetec Cougar, I am not sure where the IACV is, though I believe it is on the side of the throttle body.
intake manifold runner control malfunction (stuck open)
on the back right side connected to the intake manifold close to the firewall
On a 1997 Mercury Cougar XR7, the temperature sensor is located below the air intake. The sensor should be accessible without having to remove any other parts.
it's located on the firewall right in back of the intake
There are a couple ways to do this. The cheapest and easiest is to install a cold air, or RAM intake. Another great way is to purchase a performance programmer. Programmers can increase power and fuel efficiency. You can get both for about $500
The IAT sensor on a 2000 Mercury Cougar V6 is on the back side of the filter box. On the Zetec model it is either on the Air box like the V6, or on the intake tubing running from the box to the Throttle Body.
take off intake and have small fingers
Your intake manifold probably has a crack in the water jacket.