A Couple Questions After Long Road Trip

Just did 2,675 mile road trip w/most of it being 225 miles, stop 5 minutes for gas then another 225 miles, repeat up to 1,100 miles in 1 day. A couple things I noticed that I haven't before.
1) when the A/C compressor kicks on (after loooong highway runs & sitting idle @ a red light/stop) it vibrates the whole truck. It does not do this on shorter trips.
2) when applying the brakes after coming off the highway (after loooong highway runs) the brakes thump pretty good when coming to a complete stop. Like grabbing real hard & then they'd release real hard. Both with a decent bump to the whole truck.
3) the longer I drove, the worse my fuel mileage got. Started @ ~15.75mpg & ended @ ~13.25mpg (same terrain/speed/altitude/etc.)
These are new situations & only pertained to the long non-stop highway runs when getting into a town/traffic.
Any clue as to why any of these would be happening?

 

I'm impressed, I did 990 once and thought that was a lot.

The AC and brakes I have no idea. Except the problem may be between your ears.

Fuel mileage can vary a lot depending on gas quality in different regions. But wind direction can make a difference too. In 2016 we drove my Tacoma from GA to the Grand Canyon, up to Zion, and other areas of SW Utah. Overall about double the miles of your trip.

Going west we took the southern route through TX, NM and AZ. Coming back we crossed CO, KS and MO on a more northern route. I kept the speed as near 70 as possible and averaged 20-21 mpg on most interstates doing that regardless. Once off the interstate in AZ and UT there were very few places where 60+ was possible. That combined with lots of long downhill coasts got me 22-23 mpg for several tanks. There was some city driving thrown in and poking around at slow speeds inside the parks resulted in poor fuel mileage on a few tanks.

The only exception was on the return trip. We hit a strong, steady headwind in Denver and drove through it until about Kansas City. I only got 16 mpg on that stretch. From the MO line back to GA I was back to 20-21 mpg and the overall average for the trip was 19.9.

My truck is basically the same as yours, except 5 years older.

 

Have you checked for a vacuum leak?

 

A/C compressor could be seizing up

Brakes could be seizing up or the rotors are simply warped

 

I've ran it for several 100 miles since the road trip & neither are acting up like they were. Just curious why it'd happen after extended run times.
83K miles on truck. Thanks.

 

Range is only 225? I’ve stretched to 420 range before. How old are your plugs? Tire PSI? Last oil change? Radiator flush? Cruising speed? RPMs?

 

New plugs
Tire psi is 38 front, 36 rear.
Oil change was right before trip
Haven't flushed radiator yet
Average speed was 75mph
RPM's were ~2,200
None of these issues have happened since that long road trip. Weird shit.

 

Bingo. Keep it under 2k rpm and you're golden. I tend to drive like a grandpa.

 

I had 1,100 miles to drive in one day so I was looking to get it done as fast as safely possible. I usually drive slower.

 

I just did 2,000 miles through Arizona, Nevada, and CA and I experienced non of those issues. I was getting between 18 and 21mpg with some pretty strong headwinds. I actually got as high as 29mpg going over Tioga Pass thru Yosemite.

 

I just did about 1900 miles, worst mileage I got was 18.5 and that was pushing 85 for a couple hundred miles with strong winds. Probably averaged just about 20-21 and a lot of that was 75+ and 2200 - 2300 rpms. Truck does way better @ 1800 and 60ish. After a couple of fillups this week, I think I'm starting to flush out the ethanol contaminated gas, but it will likely take several tanks. I generally only use ethanol free gas. On road trips, you gotta use what you can find. The etoh free places were pretty sketchy or way off the path for this trip.