Here is what MSD SAid, Ill let you know what I found this weekend
Well its sounds like the problem could be either a fuel delivery issue
or a ignition related issue. To help get to the bottom of the problem
check this stuff out as far as ignition related issues that you may be
having. It sounds like you may be experiencing electrical interference.
There are a number of things that can cause this but here are a few
things to try to see if it helps with your situation.
The first suggestion is to perform a full ignition system tune up. Test
all of your wires for resistance with an ohm meter. Replace any wires as
needed. Pay close attention to the coil wire since it takes 8 times the
abuse of any of the other wires. The resistance is 40-50 ohms per foot
with our 8.5mm Super Conductor wires.
Replace the cap and rotor if there is any signs of wear or burn traces
on the cap. Check and replace any spark plugs as needed as well.
Try disconnecting the Alternator to see if the problem disappears. The
alternator is one of the largest EMI generators in an automobile's
electrical system.
If you are using a magnetic pick up distributor or a crank trigger, you
can try shielding the magnetic pick up harness from the crank trigger or
distributor with some aluminum foil as a temporary test. If the problem
starts to clear up I would recommend installing a PN 8862 shielded
magnetic pick up harness to help dissipate electrical interference to a
common ground. You may also want to keep the coil away from other wires
and the MSD unit by at least 12". If you are using the points/amplifier
wire (white wire) to trigger the MSD unit, try isolating the wire from
the other wires it may be running along with. You can try shielding this
wire with some aluminum foil as a temporary measure to try and isolate
the issue.
Try re-grounding the electrical system of the vehicle. The grounding of
a vehicle should be like a ring or a loop. Try these steps-
1.) Replace existent battery cables with high quality replacements,
an upgrade to 0W or 2/0 gauge is recommended, and the use of fine
stranded cables ensures great conductivity, durability and flexibility.
Strand density is important...regular battery replacements have stranded
copper wires in the tens, while fine stranded cables are in the
thousands. They're more expensive, but worth the investment due to their
low receptivity, flexibility and ruggedness to heat.
2.) When you visualize a typical ground circuit, need to look at it,
as an electrical loop. All electrical/electronics equipment are
sensitive to noise, electrical variations (spikes/dead spots) and will
affect either accuracy (gauges, sensor outputs, ECM), control quality
(DC frequency voltage for actuators like IAC/Injectors/Solenoids), or
the lifespan of the equipment in use (alternator, starter, ECM). The
connections that make up the "ground loop" are:
1.Battery Post-to-Engine
2. Engine-to-Frame
3. Frame-to-Battery Post (ends where it started).
3.) As mentioned above, an upgrade to fine stranded battery cables
is recommended, along with an upgrade to 1/0 or 2/0 gauge. Any contact
point to the engine should be stripped of paint. AN engine block
location is preferred, but the use of the cylinder heads and the timing
cover is acceptable. An addition to ensure a permanent and reliable
metal-to-metal contact, is the use of External Star Washers.
4.) Engine to frame: This is the most important ground connection
for gauges, interior lights, exterior lights...proper operation. It is
recommended that this strap, if it's still in place, be reconditioned or
replaced by a new one, making sure the contact points are stripped from
paint, and the use of the external star washers. It is also recommended
to add a second ground strap at an alternate engine-to-ground location,
as a reinforcement/redundant measure.
Another suggestion I have would be to install a noise filter. The PN is
8830. This is a 26kufd noise capacitor that will filter and regulate the
voltage that may be feeding back through the battery.
You may also want to check out this tech article.
http://www.msdignition.com/pdf/tech%.../tb_top_10.pdf
I would be concerned with the fuel pressure dropping as the RPM
increases. It could cause the bowls to empty out under load. You might
want to start with the filters and make sure that there isn't any kinks
or bends in the lines reducing the volume to the carb.
Thank you,
MSD tech