Ford Repair: Ford Probe Hesitation, mass air flow sensor, mass air flow

Question
Erik, I have been having this problem recently with my 1990 Ford Probe 2.2L 4cyl.  It hesitates and even stalls when I am shifting into drive or when I press the gas pedal.  I removed the spark plugs and they had quite a bit of buildup on them.  I am going to replace them just as I have done before, but I am thinking that this is not the root problem here.  I checked through my Hayes manual and compared pictures to the ones that are in the manual.  The symptoms that it lists are various, but the one that stands out to me is the one that is referring to an oil leak.  I have some oil on and around my engine, up near the rocker arm cover and almost every low lying area on the top of the engine.  There is a new distributer cap and rotor that have been installed.  I am going to replace the spark plugs and the rocker cover gasket today, but I am uncertain that this will be the fix for it.  I am also going to de-grease the engine at this time so I can see possibly where the problem is coming from.  I know that I have to add oil to it routinely, so obviously there is a leak somewhere.  But not sure about the hesitation and stalling.  
PLEASE HELP ME!  

Answer
Hello and thanks for the question...I'll try to help.
I would suggest a few things:
1. Have the computer system checked for fault codes.....repair what is needed.
2. Check fuel pressure.
3. Check the air intake hoses that go from the air filter housing to the MAF (Mass Air Flow)sensor for cracks/breaks/leaks. This would allow unmetered air to enter the engine and cause it to stall or become jumpy.

Also, fix the oil leak.

Erik