1989 Cougar runs poorly when cold, bad mileage
 

Hey all:

My dad has an 89 cougar, non-supercharged with only about 50,000 miles.
The problem is the engine runs very rough until it warms up, and then its fine but is only getting about 10MPG.
The colder the outside temperature, the worse it runs, to the point of stalling in below freezing temps.
The weird thing is that the check engine light never comes on.
The next time I have access to the car I'd like to check the EEC-IV fault codes anyway. I know how to do it but where is the diagnostic plug located?

Thanks for any insights

Its better to go to a mechanic and get the problem solved soon.he is a better person to fix it.