I want to clarify if you are asking if you can blow air through a fuel injector? If this is your question, I am not really sure what you are going to gain by trying to do this. A fuel injector has a tiny valve inside that opens with an electrical pulse from the PCM. Even if you could open that valve, the passages inside the injector are the size of a pinprick. There is nothing to be gained in trying to blow air through an injector. You will not even be able to tell how much air is going through the injector, and how much air is going around the injector as you are doing this. If the injector will not clean up with injector cleaners, then it will require replacement.
If you are looking for the fuel pressure regulator on a 4.3L, it is located under the upper intake manifold and is attached to the bank of injector poppets.
Assuming this is a diesel engine, the electrical connection for the injector harness where the harness passes through under each valve cover is known to fail. The connection is part of the valve cover gasket and is easily replaceable. When you remove the valve cover from the bank that is giving you trouble, you will see the problem at the electrical connection.
Yes, on a 4.3L engine it is located under the upper intake manifold, attached to the bank of injector poppets aka "the spider".
It is under the upper intake manifold, attached to the bank of poppets.
4.3L fuel pressure regulator is under the upper intake manifold. It is attached to the fuel injector bank.
It is under the upper intake manifold and attached to the bank of injector poppets.
The fuel pressure regulator is located under the upper intake manifold. It is attached to the bank of injector poppets (aka, the spider).
The fuel pressure regulator is located under the upper intake manifold. It is attached to the bank of injector poppets, AKA the "spider".
A 4.3L engine has the fuel pressure regulator located under the upper intake manifold attached to the bank of fuel injector poppets.
It is located under the upper intake manifold. It is attached to the bank of injector poppets aka "the spider".
It is under the upper intake manifold, attached to the bank of injector poppets.
It is under the upper intake manifold attached to the bank of injector poppets (aka the spider).