I took my car to PTP to dyno there, and it came out with 166, 169 corrected for the weather. According to the guy, that's the lowest he's ever seen and he said it's possibly due to my AEM Intake not being tuned. I'm probably going to take my car to a dealership tomorrow to get a compression test done, but I was wondering if you guys had any other ideas, or whether this is what I could expect.

your AEM intake has nothing to do with tuning... the AEM has the same maf tube diameter as OEM

AEM tuning?! RUN....
that doesn't make any sense at all (for reasons listed by Paul)

how many miles on your car?
when was the last time you changed the spark plugs? Ever changed the ignition coils?

Mustang Dyno or Dynojet?

I bought the car used with 43k miles, I have 45k on it now, never changed plugs or coils. It was dynoed on a favorable dynojet.

time for new plugs and coils.
Plugs and coils should be changed every 30,000 miles or so.

send a PM to Charles R. Hill, he has the best prices.

definitely check those out, they've been known to be a problem.

you can't tune the stock ECU.

You need an Access Port

do a decarb procedure while you are at it--did wonders for my car and I'm only at 20K miles

decarb can't hurt either

ray: get some sleep. ;)

So you're thinking it may just be as others suggested: plugs and coils?

Ok yeah, that sounds like a plan, I just need to wait a couple days to get some money together, and I'll send you a PM as soon as I do for the plugs.