OK, well let's try to narrow things down. One of three things could be wrong, air, furl or spark. Usually air is a problem with the whole engine if it is at all so that makes no sense. Fuel or spark. Did you check compression for significant drops? Are any plugs showing the engine running rich or lean in any one cylinder?
If you run it for awhile above 2000 RPM does it clear up for awhile? I'm thinking you might have another bad injector or a clogged one...I've seen a few that totally clog up where the injector meets the fuel rail...

Spark plugs whould tell the story in every cylinder.

What exactly does it do/drive like? When exactly does it misfire in the RPM range?

 

Ok i finally got it back from the mechanic, come to find out he had gotten a bad opti spark, got a another brand new one, installed it, new cap and rotor, new wires, plugs, new injector, new plugs, seems to run ok, but when sitting at stoplights, seems like it might be loading up a little bit, running rich! I put it in neutral and rev it up to about 1100 rpm, it clears out, taking it out on the freeway on the way home (about 120 miles) i opened it up a little bit, ran perfect up till about 4500 rpm then it blubbered, and noticed some hint of black smoke (rich condition) but other than that, it seems to be running OK...any suggestions where to begin looking? I appreciate all the help and comments from everyone!!

 

I would say scan it during WOT with a friend and check everything, including the BLM's. That can tell you alot about the engine like if it has a vacuum leak, or if it's running rich for no reason. Look for anything out of the ordinary when the engine is acting up...

For some reason I keep thinking fuel pressure regulator or plugs... more plugs than anything.

When it stumbles and clears out over 1100 RPM, does it idle fine for a little while before stumbling again or does it automatically resume?

As far as the stumbling goes, if you were dumping fuel into the motor or had a weak spark, the plugs may just be fouled. Should have cleared up on the drive home, but you may have a bad plug or two. I changed my plugs before because of this. See if you can narrow down which side is running rich using a scantool reading the o2's, then pull the plugs to check.

 

When it stumbles and clears out over 1100 RPM, does it idle fine for a little while before stumbling again or does it automatically resume?[quote]

exactly what its doing, idles fine for a while, then will stumble again! you hit it perfect!

 

Mine did the exact same thing before. Let the engine start stumbing, then shut it down and check your plugs. I put new ones in with wires and still had a problem. Turns out I had a cracked plug, but if they're fouled they can do the same thing. I put some NGK's in there in place of the new A/C Delco's and it's run perfect ever since.

Make sure to check the injector on that cylinder too. Easy way to check is to swap out the injector from a known good cylinder, like the one you have that is new, and see if the problem moves there...will tell you if the injector is bad if the problem moves with that injector.

Since it will run fine for awhile and then start stumbing, I think spark delivery is probably not a problem either, but double check to make sure that wire didn't burn or come loose during installation.