Well, that's a whole new kettle of fish. As described, your problem reminds me of a similar lack of performance in my old 1954 Packard when the exhaust manifold valve broke and got stuck closed -- and when warmed up, the car started acting as snarly and sluggish as if someone had shoved a banana up the tail pipe, hardly any power at all. Perhaps you do have a "breathing problem" of sorts via the air intake or some other calamity. I suppose you could have the coils checked for output before replacing them for it sounds like you're problem could be elsewhere.