Land Rover Repair: 96 disco hesitates, mass air flow sensor, mass air flow

Question
Hey John,
  My 96 disco starts out fine but after about 30 miles of driving she begins to hesitate intermittently. Lasts a couple seconds, run fine for a couple of seconds, hesitates again. Shop replaced coil pack and fuel pump. This didn't fix problem,(yet set me back a few). Shop claims that those parts were bad and needed to be replaced anyway.  They claim cylinders 5 and 7 were receiving no fuel or spark.  Any hoo I refuse to take it back and am now once again on my own in land rover limbo.  I'm thinking mass air flow sensor or clogged cat. any thoughts? Thanks
P.S. Sometimes I can drive all day with no problem  

Answer
There is a good chance you have intermittent sticky valves inside the motor.  You may want to go to my web site and read the magazine article reprints on that.  Go to www.robisonservice.com > service > land rover > articles and advice

A mass air flow sensor would not be intermittent, nor would a bad cat.  They are not part of this.