I recently purchased a great 1 owner Lariat which has suddenly developed a low idle and cuts off when coming to a stop. Prior to this, the truck had idled high but never stalled. Also believe gas mileage has decreased at the same time. The only thing I did prior to this happening was clean my battery terminals - can't possibly be connected? Any ideas?

Also, has had a very sloppy shift into OD from the get go. What's the cure? Thanks.

 

My guess vaccum lines..

Check them carefully..

I have a 87 and I found out that
three of my vaccum lines ( THOSE cheap red hoses )

Were leaking...

I broke one just touching it.

If not go through the CAP, ROTORS, WIRES, COIL
transfre, it also more never fails..

 

low idle and shuting off when stopping are definate signs of a dirty air bypass valve. Very easy to clean, just take off the valve and spray it good with carb cleaner. Also spray in the two holes where the valve mounts on the throttle body. Cleaning the throttle bores themselves, will help also. My 90 F-150 5.0 was acting the same way, and cleaning along with a new cap & rotor fixed it right up.
As far as the transmision, mine has a rough OD also. I've driven it like that for 10000 miles and it hasn't gotten any worse. That's just daily driving though, no heavy loads. The AOD is basically a car transmision and isn't really strudy enough for a truck in my opinion.