Hi Mike,

Well your to be commended for staying with it.  I have been asked
several times over the years to fix an engine's faults while being told
to ignore a noticeable major fault in the process.

I feel bad saying this, but until BB or someone solves the low
compression on #3, I would forget about "fixing" or "adjusting" anything
else.  My main point is that you cannot expect #3 to burn all of the gas
it's receiving, since with lower compression it's burn rate is low.
This means that probably cylinder 1, 2, & 4, are running lean, i.e. low
power, and #3 is dumping raw fuel into the exhaust stream.

The above scenario explains why The O2 is coated with soot, and yet the
readings from the O2 sensor read in range, .3 - .7 volts-- this is an
average of all four cylinders. Therefore with one cylinder running rich,
the other three must run lean to compensate. Low power results from a
lean condition and from only 3 cylinders producing reduced power with
one overrich cycled producing even less power than the other three.

Said differently, the ECU believes that it is feeding the engine fuel at
the correct amount since the O2 feedback is good.  But in reality, the
feedback take a all four cylinders into account. In order to
successfully run one cylinder 30 lb. LOW, the ECU would have to cut it's
fuel ratio separately.

The compression issue needs to be solved. Like many on the list I've
built engines. Used to do 2 or 3 a week.  Putting the rings on so that
the gaps are offset, valve set-up and etc., are possible quality control
items.  If Bob is not a one man shop, then it's not always possible to
watch everything that goes on. I feel that you've dutifully double
checked your end of the deal and are entitled to have the #3 cylinder
taken care, assuming normal circumstances are present.

Sincerely,

Mark Keller
91 Carat