***HELP! Car bogs under acceleration!***

[Rsporty]

Just added a built head to my Ls motor and had it tuned about 4 weeks ago.
Been running great...until yesterday.

It idles and revs just fine, but when I give it gas and let off of the clutch to start driving, it bogs down really bad almost like it's gonna die, then jumps and jerks, trying to catch back up.
I swear it probably looks like I can't drive a 5 speed!
If I push the clutch pedal, it revs back up, but as soon as i let off of the clutch it bogs, again.
I have to rev the Hell out of it and ride the clutch, just to get it moving.
Once I get moving, it does it every time I change gears and let off of the clutch.
Once I'm up to speed it's fine, but if I let off the gas, it bogs a little then picks right back up when I give it gas again.
It started, yesterday, and seemed to get worse as the day went on.

I have no CEL's.
TPS and MAP are brand new.

I'm thinkng it's fuel system related...
- Maybe my fuel pump is going out?
- Clogged fuel filter or injectors?
- Bad gas (I filled up, from empty, the night before)?

OR could it be ignition related?
- NGK plugs, Autozone (mid grade) wires, cap and rotor are all only a few months old and LOOK fine.
- I checked and the timing belt hasn't jumped a tooth or anything like that.

I appreciate any help or suggestions, very much, and rep points will be given.

Thanks, IA!