hummmmm....I hate intermittant stuff. The fuel PSI #'s look a bit on the low end of the FSM listed range? Clogged strainers in the tank? You checked the regulator hose for gas?....long shots, I know.
what about
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Are the O2's new? How are the m/volt and cross count readings?
Excessive oil in the MAP hose and therefore in the MAP vac port?
Also the electrical side of the MAP? The voltage is suppossed to change with changing vacuum.
TPS, I would want to check if it was going thru it's voltage sweep in a linear fashion....ya know from .54 @ idle and it changes correctly as you advance the throttle.
It will not do it if the car is running with a scanner on it in your driveway? I was thinking that if you could duplicate the miss with the scanner hooked up you might see something in the O2 #'s or the fuel #'s....and you could check the MAP and TPS voltage responses. Sorry I'm full of answers, hugh?
If it were me I would redo the fuel pump test, scan the car, see if I could get it to miss in the bay so I could smell the exhaust....might tell ya something. I usually keep last yr's plugs....I use the std GM 402's...so I'd swap them just to see. I'd do a spark intensity check. Re check all my EEC plugs and then be lost if I didn't find anything.....oh battery & alternator voltages just to be sure because it sounds like it has to be hot for the miss to occur, right? That's the nice thing about the scanner, hook it up & let the car get hot and watch the outputs.
Tom