91 200 TQ Wagon stalling

[Watts]

Hello all,
New to this list, I just purchased a 91 wagon, RS EM and RS Turbo with
Hoppen stage 2 chip. The car is in exceptional shape, has been serviced
by 2Bennett most of it's life. The previous owner was meticulous in his
repairs and upgrades, and fixed things promptly. I put about 2k miles on
it driving back from Sacramento to Colorado, the car performed
flawlessly, unbelievable acceleration, ran cool through the desert (105
deg.). Yesterday I started off from a light trying to keep up with an
STI and after a shift to second the car started missing badly, pulled
over, the car would idle but I could not get it to run over 2k rpms, it
just sputtered. Tried several times with the same result. At first I
thought I might have blown one of the turbo or IC hoses off, but they
are fairly new and tight. Went to call AAA for a tow, came back 30
minutes later and the car started right up and drove perfectly. Took it
down to Sport Wheels and John Beckius was a little stumped (perhaps
because he was trying to get out of the shop for a vacation). He poked
around a little, and said that the fact the car started back up
eliminates a lot of the typical causes of this kind of problem. He did
not think a small or even loose hose would cause my problem, it would
run poorly without power, but not as bad as my car was running. He did
not think it was fuel related. He thought it could be an electrical
problem (hall sender?) that occurs when it heats up and goes away when
it cools down. Any one have any thoughts?
Greg