Ok these circumstances might be a little hard to replicate but here goes...

Running stock boost levels (when I want to save gas), I generally run around town at 3/4 throttle. It boosts to roughly 7 psi, shifts at ~4000 rpm etc.

So here's my problem, when the engine is warmed up (its worse when cold) I floor it to 4000 rpm then let off to 3/4 throttle to allow the tranny to shift (tranny hates shifting at full boost for some reason... no big deal) and when I let off there's a distinct miss like "bam...bam...bam" and then the tranny decides to shift.

Any ideas what might cause this kind of miss?

New plugs, wires, distributor. 1994 B230FT converted to LH 2.2 "etc."

I have a leak between the manifold and the turbo, and I think on #4 cylinder exhaust manifold gasket. Since these are pre O2 sensor, is it possible these leaks are causing or contributing to this issue?

Thanks

Ryan