Naw, we use that too, to richen mixtures up, and to see if a car that is a no-start or a crappy running, almost stalling POS is doing it because of fuel.
See, if you hit it with Propane(or brake cleans, or WD-40 etc) into the throttle body, and it runs, you have good ignition, good compression, good cam timing etc.
If it doesn't fire with the propane, brake cleens etc, then it must be another problem. Its just a very simple first test.
It will richen it up as you are adding fuel that is not being put in by the ECU.
I am tending to think that if your car is ok when on boost, it must be a sensor of some sort. Not O2, that is not in use really when on boost. I would have a look at TPS, MAF and your ECU temp sensor.
And just because your caps are good doesn't mean your ECU is good either.
If you can find someone near you with a car the same as yours, that works fine, you could swap out parts like MAF, TPS, ECU and see.
Check wiring at the ECU temp sensor. Its on the thermostat housing down low. Not to be confused with the temp guage sender.
Get, beg, borrow etc a logger too. It can tell you sensor readings and voltages. TPS is supposed to be a certain voltage (0.48-0.52 volts) as are all the other sensors. If one is wonky, you can start there.
