MC2 Running Lean

[Scruggs Family]

My '87 5kCStq exhibited the same symptoms when running under boost...
missing, loss of power.  I, too, changed everything that could be changed...
plugs, wires, distributor cap, injectors, fuel pump (twice), fuel filter,
warm up regulator.  I metered, as best I could absent an oscilloscope, the
inputs and outputs of the ECU and found nothing unusual.  I measured the
fuel pressures cold and warm and found them to be 'within spec.'  

Then in about '01 someone on the list happen to mention that the CIS overall
system fuel pressure is set by a small spring located at the front of the
fuel distributor.  I removed said spring and put a washer behind it to
'stiffen' the spring.  The engine immediately ran better... much reduced
missing under boost... a significant improvement in performance.  Give it a
try.  

I have since bought a rising rate fuel pressure regulator to address the
issue but have not yet installed it... but it's in the project queue. 

Gross Scruggs
Annapolis MD