after 1hour or 2 car starts to die

I have a 2000 Honda accord ex v6

After about an hour or two, the car wants to die on me.

Idle drops , power drops, engine shakes and if i leave it alone it dies, but if i rev it a min or 2 while it's doing this, the problem goes away.

Plus some times (intermittent) while driving for a while, and stopping the car for a min or 2, the car starts and dies right back. i have to give it gas just to keep it going and rev it so it will run. Then it's fine.

It was giving me 24miles on the gallon, now it's 19miles on the gallon. check Eng light came on; misfire code.

Things checked an done to it:

coils: checked fine

cam sensor: replaced

crank sensor: replaced

alternator: replaced

injectors: checked and serviced

radiator: purged for any air

Note: another way to stop the idle drop, power drop and the shaking is by removing the vacuum hose to the fuel regulator. ( idle does increase a little, in between normal idle and 1000rpms) i don't know if power comes back with this procedure since I'm a little afraid to drive it in this condition, because i don't know if it may catch on fire.

Please Help.

any input is appreciated.

Thank you.