My ford focus 2008 misfires and hestates at take off?

Just bought the vehicle driven for 100k miles and I discovered the evap system is disconnected from the fuel tank. Also I have cleaned the maf sensor several times including the injectors and replaced the spark plugs but no Improvement. I'm considering changing the maf sensor but one other thing that worries me is the check engine light does not lit even when I drove for some miles with the maf sensor disconnected. But the vehicle smoke is clear, not black though. I will appreciate any useful tip that can get my car out this condition God bless

Does the check engine light come on during pre-start check (ignition on)? Could be a burned out light or removed.
Check the coil pack - I had an older focus and somewhere in the 100k range the coil pack needed to be replaced - I could see cracks in the housing - (amazon for <$25 was good enough and $60 cheaper than a fomoco coil pack).

With the EVAP system disconnected and no engine light on I would suspect the MAF sensor is being doped somehow. Check the voltage going to the MAF I think you'll find there isn't any. Follow the wires back.