Engine lags
 

I am having issues with power getting in 1st. I have to Rev it around 25-2800 RPM (depending on if my AC is on) to get it going. And sometimes it will shutter. My 2008 only has 86k miles and everything is still original except the starter. I just did a drive from Reno to Roseville and I noticed during a quiet part of my radio I hear a metal flutter in 5th gear excellerating a hair from 80MPH to 81, 82ish.
Ford states that the plugs are good for 150 miles, but i wonder.

Automatic or manual? Either way it sounds like clutch/pressure plate on flywheel if manual, or if auto, clutches in the trans or low fluid pressure, which means the clutches probably smoked as well.

Its a manual. ****, I was kinda thinking it may be the clutch. How many miles should a cluch last?

Without more info, it sounds like the clutch not engaging with with the flywheel, pressure plate not putting enough force on the flywheel because the clutch is smoked. Which means the flywheel is scored and the clutch discs are smoked as well. But that's an online diagnosis, don't take that to the bank.

That's tough to answer as the history of the clutch use has to be known. If you are the original owner then it should be lasting well past 100k miles under normal operating conditions, unless you learned how to drive with a manual in this car and never really got the hang of it for awhile. That can wear them out prematurely. Now if you are a second or 3rd owner, yeah, they can get bad much quicker especially if the prior owner raced the car or couldn't shift worth a crap. That is the big unknown.
I've owned two manual Mustangs since new and neither ever needed any clutch work. I've found the Ford clutches to be good overall. An '82 4 speed that racked up 60,000 miles before trading it in and my recent 2007 GT 5 speed that racked up about 65,000 miles before trading it in. No signs of trouble in either ride. I feel both would have lasted those 100k miles. Your 86,000 miles isn't exactly low miles, so if the clutch is indeed the culprit, it's just due. A pricey repair but you will be good to go again.

First, welcome aboard! I also agree with the above statements regarding the clutch and flywheel as requiring replacement... Despite what Ford stated about the spark plugs being good up to 100k miles? I would still consider getting new plugs anyhow just knowing your car has 86k miles and is now 15 years old... Anyhow, just saying... :dunno: