There is much debate about the "adaptive" capabilities of the early processors. I have been told that the early EEC's do not adaptive learn at all. So adjusting fuel pressure WILL have a direct effect on AF ratio.
However, that being said there are several other things to consider in this case. Before you can begin "tuning" the car for performance you must ensure that you do not have a mechanical problem.
1. Do you have proper fuel pressure under load? Pressure should rise pound for pound with boost. I have seen many different situations which resulted in insufficient fuel pressure. Bad pump, leaking in-tank connections, insufficient pump size, pinched lines, faulty regulator and I am sure there are more.
2. Do you have an exhaust restriction? You didn't talk about exhaust but this is very important.
3. Is the motor using any oil? Bad valve seals or rings will cause excessive detonation. Are the plugs oily or sooty?
4. If your PCV valve is not new, then get a new one from Ford. A bad PCV can cause detonation as well.
5. Is your EGR connected? (does a 92 even have EGR?) I don't know.
Best bet then is to get the car on a dyno and watch the AF ratio. You need to know if you are close to being in line or not.
1. As a quick fix you probably need to retard timing. To do this, remove the octane plug next to the diagnostic port. This will retard timing 4 degrees and help control detonation.
2. You should already be running cooler running plugs. I recommend Autolite APP103's if you run the car hard and APP764's if you don't.
3. You should also be running the engine cooler. Do you have a 180 degree thermostat in the car? You can even run a 160 if you want but most people don't like it that cool. I have noted no detrimental effects from it over time, but you will get lots of opinions here.
4. I assume you have the proper MAF to run 42lb injectors?
5. If you have the stock IC, then anything over 15psi is a waste of time and all you are doing is superheating the air charge. you might want to find out just how much boost you are really getting.