HI Guys

looooooong time since I'v been here, I hope this is not a very long shoot,

My Shorty 3.5 (1996 NJ SWB A/T 3.5) engine started deteriorating recently, it would Idle sort of Fine (bit Rough but fine), however when I depress the gas paddle the engine would almost Stall & as soon as I take my foot off the gas engine RPM would go up.
one of the worst episodes was when I kept it idling with the AC on for about 15 minutes, then the Engine would instantly die once I hit the gas (in gear or in neutral)
Once the engine RPM goes up, I can sort of feather the gas & it would run fine.

this is occurring whether car is hot or Cold, but its worse when cold

these are some stats
- I know that I have a Vacuum Leak from the Butterfly valves which can be heard easily, but this was there when it was running fine
- I recently cleaned the Idle Control valve thing (the name escapes my now -_- ) but same issue
- checked if any of the MAF or the TPS were not working by disconnecting them & observing the engine go to limp mode with check engine light, they seem OK (did not check with a multi-meter yet)
- I know the engine needs at least a Valve Seal job as it smokes bad at traffic lights


any Ideas, help would be appreciated