Open loop is best for racing. It ignores the sensors and dumps as much fuel you need. The downsides of open loop is just that - it ignores the sensors. The car usually runs rich as hell in open loop. The car is in open loop during the first few minutes of start-up, until temperature is stablizied.
The car will drive, but you may dump a lot of gas in the process. If you haven't replaced your spark plugs in a while, you may want to look into doing that after you get your problems fixed. If the car runs rich for a long(er) period of time, it will wipe out the plugs.
Joe