i have a 2008 f150 with the 4.6 v8 i recently went camping and riding and was on alot of dirt roads so when i got back i cleaned my air filter its a fram washable i gently blew it off then washed it in straight water let it dry completely on my hood for a few hrs since its well over 100 in vegas went to drive it the next day and with the ac on at stop lights the idle drops and will stall sometimes the idle doesnt jump above a normal idle just will drop to a low idle and only does it with the ac on theres no codes at all the truck had similar problems before only the rpm would bounce up and down with the ac on or off and the dealership put a new throttle body in and i had no problems since till just the other day im at a total loss

 

is your engine light on? if so, check your camshaft position sensor plug, happened to me after i had to dig a screw driver threw my oil filter cause the d**khead that changed the oil before i got the truck decided to use an impact wrench so it was almost impossible to remove

 

try cleaning you maf as well....

 

If it turns out to be your TB again I would start checking out your wiring harness for shorts. Something is killing your TBs maybe.

Definitely like the others said, clean the MAF with special MAF cleaner. You would most likely get codes if it were the crankshaft sensor, but the computer doesn't always find the answer either. Some sensor on your truck might be heading towards death, but not enough for your computer to throw a code. It happens all the time. Could be a camshaft sensor as well, again you would most likely get codes.

 

i havent gotten a check light at all

 

...is the throttle body dirty?

 

I had my truck in for service the other week to find that the fuel filter was almost totally clogged. This was at 45000 miles. Not to mention I try to always go to the same station in town which is a Kangaroo that is only two years old.

 

my fuel filter is less then 20000 miles old and i cleaned the tb it wasnt very dirty at all it hasnt done it since i cleaned the tb but its possible i just havent driven it enough it the heat yet but im hoping cleaning the tb did it