an odd stumble
 

I have had this 91 supra for around 10 years. Some years ago I started having problems with anitfreeze lose and eventually at 199500 miles decided it was time for a new long block. Got one from Jarco here in Atlanta. Put a new(rebuilt) turbo on it and cleaned everything else. Replaced worn parts as I came to them. The car runs great except for this. At any stable RPM (be it hi or low) I can feel a bit of a skip/studder every few seconds. Just tried changing the coil packs. That was not it. Does anyone have any ideas???? I am stumped

Did you change the HT leads (wires as you say in the US)