Try some ice cold medium or retracted gap plugs gapped to .015" to .010".
This will show up a secondary ignition problem. If the problem goes away, the
voltage at the plug is too low for conditions. Mazda plugs are too high a heat
range
For climb and high load 12.7 mixture (or richer) on the (Heated) Fuel air
gage, and or 1600 degrees on the EGT.
You can also try pulling off just a bit of throttle to see if that clears
it up.
Also indicative of a secondary ignition problem.
Be sure primary ignition wires are run well away from secondary ignition
wires, and away from each other.
Lynn E. Hanover
In a message dated 6/21/2011 12:19:49 A.M. Paraguay Standard Time,
bktrub@aol.com writes:
I'm going to ground my airplane until I get to the bottom of this. I can
tune it on the ground and it will run just fine all the way from idle to full
throttle. I get about 5300 rpm at full throttle at 29 in hg. MP. I have 12
hours in the air so far but can't get past this issue. Other than this, the
plane is an absolute joy.