i have an automatic 94 dodge spirit 3.0. when its in neutral and i floor the gas, there are no problems. in neutral the cars runs perfect. when i put it in drive, i need to accelerate slowly. if i give it a generous amount of gas, it feels like the engine stops pumping for a brief moment till i release the pedal which then the engine recovers quickly and is fine. i replaced the plugs, wires, fuel filter and pcv valve. i have been told it may be the o2 sensor. i did the key trick and it told me 12,55. that 12 means the computer has been recently disconnected. i dont think that means anything. this problem only occurs while giving it gas in low rpms in first gear. 2nd and 3rd have no problems at all. i checked all the vacuum hoses i could find and replaced one. im sure it helped, but it still has the problem.

a side problem. while in drive or neutral ( i dont have a speaker box in my trunk) every 4 - 5 seconds my car increases its rpms ever so slightly when i am holding the break and not moving. when it does this, the lights dim slightly. i dont have the wipers going so that high drain device isnt doing it. also my lights are off and radio is at reasonable levels. any thoughts.

Check the O2 sensor and IAC(Idle Air Control) Motor. Could also be fuel pump, one of a million relays or sensors, ect. One other question: Does it do this once its warmed up or only when its cold?

it does it always. warm, cold, it doesnt matter.