Fired up. Manifold pressure sat at 10.1 and dropped to 9.0 in drive or AC on. Stable
Wiggled and jiggled and tickled everything I could think of. Pressure is solid,
New oil fill cap, very tight.

Long term fuel trip sitting on 9 and 12 % Short term cycling from 0 to 3 %) Maf stable, it and vacuum react as expected to throttle.

Driving me batty. About only thing I can do is swap the MAF for another new one (Bosch) I have. Am at the "throwing parts at it" stage.

Problem is that is just occasional and usually at a stop light (hitting brake does nothing). Have exhausted the usual suspects. Any ideas ?