[Tim Rif]

I just installed a 454 TBI long block in my '89 Silverado. When I first fired it up it ran great. I adjusted the IAC (which I shouldn't have) to get the engine up to 1500 rpm's for about 15 minutes. I backed the IAC off after 15 mins (back to around 1000 rpm's) and it ran pretty rough (didn't want to stay running). I drove it and it was real hesitant, stalled a few times when I stopped, but when I gave it about half throttle it would take off and run great, especially under a load or going up a hill. I took it to a shop and they said one of the injectors was barely dropping any fuel, so I had the injectors rebuilt. I also replaced the fuel filter, EGR valve, O2 sensor, and now the truck idles worse. When it is cold, it has an irratic fast idle (it speeds up and slows down). When it comes down off irratic fast idle, it really runs rough. Now I am getting an occasional SES light. I checked the codes and I am getting a 44 code (lean exhaust). I disconnected the battery for a minute, but still getting an occasional SES light with the 44 code. I took it back to the same shop that said one of the injectors was bad, and they say one injector still has an abnormal spray pattern. I called the injector place and they said they have rarely seen the TBI injectors go bad, especially after having them rebuilt. The mechanic said he checked everything (fuel pressure, vacuum leaks, injector voltage, etc) and he is stumped too! Any suggestions would be highly appreciated! Thanks, Tim