Code 44, Problem.

[1990cavz24]

Got a Code 44-Lean Exhaust Detected the other day and a miss along with it and finally got a chance to hook a scanner to it today. The o2 Sensor itself seems to be working fairly quickly, didn't seem like it was sluggish when looking at it with the scanner. Block learn value was at 138 until closed loop and then jumped up to around 156, fuel pressure is at 42 psi at idle, did an injector balance test and it came out okay, so my question is what else should i be looking for? The only other thing I can think of is maybe the miss is setting the code 44 by o2 sensor picking up the extra oxygen from the cylinder that's not firing it's thinking it's too lean. What do you all think?

Another thing, i only seem to get the code 44 when i'm at idle for over a minute or 2. If I clear the codes and drive as soon as the car is started I don't get the SES light until im at a stop light.

The vehicle is a 1989 Z24

[1988GTU]

Could also be a sticky EGR? Not sure on it though.

[1990cavz24]

Alright, Just got finished putting new plugs and wires on the engine. I cleared the codes, then started it and drove around the block for a minute to get it up to temp. It was all going good so i pulled back in the driveway and was sitting in the car with it idleing in park. It idled smooth for about a minute and then bam, SES light with a Code 44 and it started to misfire again with the idle going back and forth from about 500 rpm up to about 800. If i rev it to around 3000 while it's doing this and then let it come back down to idle, it idles smooth again for a couple of minutes(with the SES on) and then starts to misfire again. The EGR is almost new so i wouldn't think it's that. What else should I check?

[1990cavz24]

anyone?