TrboHead

Well.... I don't know if this has something to do with it but I had to rebuild my starter the other. It now turns the motor over much faster than before. My theory is that if the starter could not turn the motor fast enough to crank on the first crank then by the 3rd or so crank the injectors would spray excess fuel in the combustion. This would in turn make the car run very rough at the initial start giving false 02 reading, mass air, Fuel ratio etc. until it cleared out a bit. This is why you have to keep the rpms up to clear it out.
Just my theroy. It has not stumbled so far.

TrboHead