I was looking through my engine bay while working on my horn when I realized a sort of wired kind of plug in laying on my timing belt. I t looks to be coming out of the engine or the TPI but I have no idea where it is supposed to go. Any one know?

 

See the plug on the bottom of the MAF sensor in the upper righthand corner of this pic? yeah, it goes there.

And that's not a timing belt, your engine uses a chain for that and it's not exposed.

 

This thing? ---------------------------------------------------------l
Under here? --------------------------------------------------------v
What does it control because I dont know that much about engines.

 

See attached.

Essentially, the thing that it plugs into measures how much air is being sucked into the engine.

 

So could that not being plugged in cause a decrease in power and a decrease in fuel economy?

 

Right

The car goes into limp mode without the MAF plugged in. How long have you been driving it like this?

 

I bought the car about 4 months ago and I knew it was feeling slow because my moms 195 hp mustang was beating my car which is supposed to have 225 hp. Plus I noticed that the car would not shift into 4th gear. I just took it for a test drive and already noticed it was driving way faster than it was and now it shifts into fourth gear. The guy who had it before me had the engine rebuilt and now it has 20,000 miles on it so it could have been for that long but I dont know. So why do you ask?