2000 Ford Focus • 1.6L 4 cylinder 2WD Manual • 168,300 miles

I have a 2000 Ford Focus, it has a manual transmission. When I go to accelerated it feels like the engine is in-taking air but the check engine light has not come on and the car has not shut off. The MIL light does work. I have been getting a lot of suggestions and I don't want to spend money on something I don't need right now, plus I cant afford it. My second issue is when acceleration I hear like this grinding sound coming from the engine. I have heard that it could be the gear box, but i'm not sure does this usually go bad. I have also been told that I should just do a tune-up and that should take care of the hesitation. Please help!
May 23, 2014.

Try cleaning the throttleplate on both sides and iac hole with choke cleaner then check fuel pressure with a gauge autoparts rent it. For the noise see if it does it in all gears or just one as that can tell whether it's a trans or engine problem.

May 23, 2014.