[urq] stumble at high boost/full throttle

[Eric Harten]

Had the same issue recently.  I was leaning out bad above 12psi all of  
a sudden.  Thought I had a tank flow issue or ignition problem.  Turns  
out my 2 year old fuel pump was going south.  Worked like a champ  
below 20psi, but couldn't keep the flow up above 12 psi.  New pump and  
all was well.  20psi no problem.  I have 034 now, but I ran 15 psi  
with no issues on my chipped MAC02.

Eric