Electronic Fuel Injection Problem

Lately My 92’ GMC truck has been experiencing problems…pretty major problems. There seems to be a problem with it’s #1 Fuel Injector (on the left side facing engine from front). The injector completely shuts out most of the time and a funny thing happens…I hear what sounds like compressed air coming from said fuel injector, No gasoline coming out and I can’t feel the air (I know I shouldnt be sticking my finger in the fuel bowl but what the heck I cant figure this out!)But it definitly sounds like air.The truck rattles and shakes and shuts off 50% of the time…The other 50% of the time it will hold the speed you were at at full throttle but takes a hell of a lot of encouraging and about 1 - 3 minutes to get up more speed. After about 10-15 minutes these symptoms alleviate and the truck jerks back up to normal and I quickly take my foot of the throttle. So for my first question: Where is this air coming from? From what I understand the fuel system compresses the gasoline without air…am i wrong? And if it does compress without air where might the air be coming from? I’ve pondered the fact it could be electrical but that doesn’t fit the description to well. Any dopers out there with fuel injector knowledge? Its much appreciated.

I posted too soon!..The injector also makes a weird clicking noise, a very loud clicking noise when this happens. It’s almost like the fuel is coming out with each click. ALso the injector isn’t “dirty”, and fuel/injector cleaner has no effect. It seems to be particularly bad when the engine has been warm for awhile, and at slow speeds.