3300 V6 Misfire/stalling

I have a 92 oldsmoble achieva with a 3300 V6 engine. Recentlly, the car started to stall when cold first starting up. Now its has a hard time starting up. Sometimes it will miss in 3rd gear, but most of the time it likes to stall from a stop or low speeds, you can just gun it and it wont go. Also if you rev it hard sometimes it will miss, the engine revs will go up really fast then slow down in a loop. I am having a hard time figureing out whats wrong with it because all these problems are very random. There are no codes on the engine and I replaced the fuel filter recently and spark plugs and wires and o2 sensor are only 30,000 miles old. The engine has 164,000 miles on it.