[Paul Workman]

Sounds familiar...

Mine is fully ported, SW headers n X-pipe, POS Magnalfow muffs, sans secondaries (see my signature).

Sometimes...not every time...when I coast down or down-shift too, especially during some aggressive driving scenarios, it sometimes will cut out on me as well. And, as you pointed out, temperature (i.e., fully warmed up) is a factor.

If I have the clutch disengaged and am decelerating when it happens, the motor will stop. However, if the motor stalls with the clutch engaged and in gear (i.e., such as when downshifting prior to a turn), a quick blip of the throttle and suddenly it's "all good again"!

I don't recall if it had this behavior prior to the mods/porting, etc. - that was 7 driving seasons ago. But, I definitely noticed it after completing the porting and tune, as well as some hunting at idle with the clutch depressed as I'm rolling to a stop. (Soon as speed reaches ZERO, the hunting stops.)

Dominic is always tweaking his tune - I think partly because he enjoys the challenge of ever-so-fine tuning his LT5. But, none the less he seems to have achieved success and feels he has a handle on the issue. I may give him a shot next season and see what he might be able to do for my 90.

However, in the mean time,I've learned to anticipate the quirk, and deal with it should it occur - almost w/o paying attention much at all: I'm living with it...for now.

All this said, Ami's 91 ZR-1 does NOT display this phenomenon (yet). And, in addition to mine, the "TURQ MONSTER" has also been blessed with Pete's cams and tune: difference in chip and/or tune Perhaps?? We'll see...