[Elsie]

...Eucharistic miracles often happen where there is a lack of Faith- not an abundance of it.

And the Bible states:

11 Then the Pharisees came and began to argue with Jesus, testing Him by demanding from Him a sign from heaven.
12 Jesus sighed deeply in His spirit and said, “Why does this generation demand a sign? Truly I tell you, no sign will be given to this generation.” 1

Mark 8:11-12

[rmichaelj]

Yes, one should not demand miracles from God- to do so is to test Him.

But God may grant miracles even to those with little Faith:

Matthew 8:23-27

23 Then he got into the boat and his disciples followed him. 24 Suddenly a furious storm came up on the lake, so that the waves swept over the boat. But Jesus was sleeping. 25 The disciples went and woke him, saying, “Lord, save us! We’re going to drown!”

26 He replied, “You of little faith, why are you so afraid?” Then he got up and rebuked the winds and the waves, and it was completely calm.