Djnrg,
There is no MAF sensor on these cars. MAF is mass air flow. Those are located after the filter and before the throttle body. They measure how much air is passing through them and tell the computer, so it knows how much fuel is needed. On an Intrepid there is a MAP sensor. This is a Manifold absolute pressure sensor. This is what you were describing. It measures the absolute pressure in the manifold (as opposed to a boost gauge which measures pressure above atmospheric). So, in theory, if the pressure went up, the MAP sensor would pick it up, and the computer would then inject the appropriate amount of fuel. HOWEVER...our MAP sensors only go to 1 BAR. Thats 14.7 psi. It will send the same signal at 20 psi that it does at 14.7. For this reason, you would definitely need some sort of fuel management solution.
As far as the idea of using compressed air....Basically you want to supercharge the car. But instead of compressing the air in real time, you want to do it slowly over time, and then release it all at once. Here are the problems as I see them.
1: Lots of weight; You will need a large heavy canister to store enough compressed air for the job. Remember...cars go through several hundred cubic feet of air per minute. A Scuba tank holds about 70 cubic feet of air (at STP). At say...6-8 psi of boost you it would be significantly less
2: Regulating the air; you need to let the air out of its container and into the intake manifold. But in the process you are going to need to drop its pressure several thousand PSI. You need to accurately regulate the flow and pressure, and at the same time make sure none of the regulating deviced restrict flow too much.
3. Compressing the air. To store a meaningful amount of air, you would need to be running at least the same pressures that scuba tanks run. Thats around 3500 psi. Good luck finding a compressor that will do that. If you look at all the compressors in a hardware store, they only go up to about 400 psi.
All things considered, its not a fantastic idea. I don't mean to offend. I've actually had the same idea myself in the past. The real problem is that air won't liquify under pressure...you have to get it cold. NOx however does. If you compress nitrous it will turn into a liquid and get much denser. That way you can store a ton of it at only about 900 psi. Its also a better oxidiser than air is. After all...you are looking for an oxidizer, so why not use a good one. The best part about nitrous is that its proven and its available. If you buy a kit from N.O.S. or Nitrous works, or Edelbrock, you can be sure you will get the power you paid for. And if you install it according to the instructions, you will also be sure that its relatively safe, and shouldn't harm your engine.
Scott