OP, let me show you what my 2010 Lariat could do in 108° weather. I've posted this many times before, ask your dealer why your vehicle can't match mine. In the 6 1/2 years I owned it before buying the 2016, I never touched the A/C system.

 

FWIW, my 2010 temp out of the vent, according to my thermometer, is 38*

 

So obviously, the a/c system can do it. The OP just needs to find someone smart enough to give him numbers like yours and mine.

BTW, a little known secret. Key Alt 248 all at once and you get °, i.e. 38°.

 

Thanks for all the replies. It really helps to have a forum like this where you can ask questions of people that are more knowledgeable then you may be on certain topics. I just wanted to follow up from some observations over the weekend. First I do live in North Texas, specifically the North Plano area. We have been experiencing some record temps this past week. I think the highest was 109°a couple of days or maybe up to 110°. When I posted the temp I was measuring at the vent the other day the outside air temp was around 102°. I only had one digital thermometer and wanted to make sure I was getting an accurate temperature so I added a second thermometer. They have been reading with one degree of each other. I started noticing the issue about a month ago when temperatures were constantly above 90°. Observations from this weekend.

1. I was in my truck three times this weekend. The outside air temperature during at these times were between 91° and 97°. The lowest temp reading I could get at the air vents was 61°.
2. This morning on the drive to work, 40 minutes, the outside air temp was 81°. The lowest reading I saw at the air vents was 50°. Most of the time it averaged between 52° and 59°.
3. Every time I stopped at a stop light the air temp at the vents immediately, within 20 seconds, rose at least five degrees.
4. I tried various setting during the drive to see if there were differences. One observation was when my fan speed was set at half, the air temp reading was two to three degrees cooler then when fan was set at full speed. I’m assuming this was due to the air having a little bit more time to cool off at the evaporator coil before being blown out the vents.
5. Even while driving I would see some temperature fluctuations of two to four degrees.

I’m not an AC person, very limited knowledge, but I do have a basic understanding and I do try apply common sense to things. I understand we are experiencing record temperatures right now. But I have owned this truck since new, 8 years now, and we have had 100° days before. I did not start experiencing this problem until last year. Last year the dealer went through the system, basically piece by piece, until they got it to work properly. This year they said there was a leak at I believe the expansion valve, I don’t have the paperwork with me right now. So after that repair they said it is fixed. I will give them one more chance to get it fixed. If they cannot then I will try to find an independent AC mechanic that is knowledgeable about Fords and see if they can figure out the issue. If not then I might try the hack from the other thread.Thanks all,

 

Op, don't give up on this, you have a mechanical problem.

Not to one-up on you, but today Vegas is supposed to be 107°, and tomorrow 110°. If you think that everyone that owns a 2010 here would tolerate a/c temps like yours, you would be mistaken. My pic shows what you can get at 108° OAT, and my 2010 has experienced 116° OAT with no problems.

I had a friend complain to me that the temp gauge on his Corvette would climb when he was at a stop light in the summer. I suggested that he kill the A/C while stopped at a long light.

His reply? "The engine can melt before I would shut off my A/C." That is why I believe that Vegas trucks don't have your problems.

 

Reminds me of the time we were on a family summer vacation when I was a kid and got stuck in a traffic jam not moving just sitting there. My Dad says "the car is going to overheat, I'm going to have to shut it off". My Mom replies "well then it's just going to have to burn up 'cause I'm not sitting in here with no air conditioning!"

 

Last Update: I took my truck back to the dealer on Monday 7/23 and picked it up on Saturday 7/28. On Thursday the service tech called me to tell me they think they have it diagnosed as a stuck air blend door. He explained with the door stuck in the wrong position it was letting to much hot air in and the AC or cold air could not compensate for it. That would make sense as to why it seemed to work better in the morning when the air was cooler versus the afternoons when it was 100 degrees. I have measured air temp of 44 degrees at the vent. So it seems to be working and I'm happy with that.
What i'm not happy with was the AC was doing the same thing last year. The last thing their AC guy said was causing the problem and fixed last year was the evaporator coil. My understanding is that the air blend door is on top of the evaporator coil. So my thinking is that last year when the AC tech disassembled and then reassembled the system to get to replace the evaporator coil he accidentally unstuck the blend door, or he realized what the problem was, unstuck it and never owned up. The AC seemed to work fine up until the winter and then I guess it got stuck again before I started using it this year.
Thanks for all the replies and suggestions.

 

Hell idk, it's more comfortable in my truck than being outside in this wonderful Alabama summer.
About all I care about...

 

I'm going to have to share that with the wife - she will totally agree!