misfire, please help

[pontiac3100]

whats up.
i have a 94 3100 gt
with 170298miles on her.
and she has some balls..lol.

anyway.
when she's first started or after i let her sit for awhile she seems to have a misfire.

rpm's between 1,100-1,300 she shakes bad.

and when i'm on the highway and the rpms under 2,000 with the t/c locked she shakes.

i've checked the coils, replaced the icm.
replaced the pcm NUMEROUS of times.
come to find out i need to have a 94 pcm for the same make model AND trim.
so 94 is a picky year.

i looked at my rapid fire 6 plugs well 2,4,6, and wll of em' have some white stuff on em.
and 4.6 also have some red crap on em'.

oh btw this site's pretty cool.
i had a gtz....

[rweatherford]

Is it white flakey ash?  If so then you probably have an lower intake manifold leak.

This may not be the missing problem, but it would be an issue.

[pontiac3100]

ehh no.
but it seems at higher rpms she boggs sometimes.
but that seems to happen when i use that chevrontechtron...