Car is sluggish

I have a 1994 pontiac Firebird Formula seems after like 5 miles it starts skipping and will not take gas . when its cold it seems to run fine .. when i floor the throttle it skipps like its running on 7 cyl. i have replaced plugs recently. Anyone have a clue or same problems i am having?

how recently did you replace the plugs? did the car sit at all after you did so? I had a similar problem in my formula a while back...plugs/wires fixed it. I'd say plugs/wires, fuel injector cleaning, maf/mas sensor bad (dont know what it has), ecu bad....in that order.
Usually when it only runs bad after it warms up its a spark problem.

try replacing the coils

try replacing the coils as well

Have a diagnostic done to see if anything comes up. You may have a misfire..If you do you'll probably need to change a coil pack since you'va already changed the plugs. :-)