As staticc says, your car will run better with them. I'd think twice before following the advice again of whoever you had working on the car with you. You need to rewire them - be sure you get them reconnected as they were before. Once warm, the computer goes from open loop mode to closed loop mode where it reads data from the sensors, and adjusts how much fuel gets injected. Without them it should run (mine were 'accidentally' disconnected for 6 years!) but it won't run as efficiently as it would if they were hooked up, and some people suffer major drivability problems without them being hooked up.