After basic tuneup still misfiring.

[Marcos]

What kind of air cleaner are you using?

 

[Southern Pride]

Mine did the same also last year when I had to put an EGR on it. It would want to fall on it's face right when you hit the gas in the low rpms to get rolling, disconnected the main vac line that goes from the valve to the solenoid and it ran fine. Left it like that for a year or so and re connected it, now it works fine I swear, these trucks sometimes....

 

[Super Silvi 1990]

I had the same problems on my truck as well hard misfire on accel and then it was fine. I replaced everything you did as well. Come to find out later on that the gas station i usually fill up at the underground tank had cracked and had water in the gas they shut it down. I had to do two castrol fuel system flushes and a fuel filter to get it running normally again. Also i ran it untill it had almost no gas left. After that it only happen when i was low on gas for awhile then it went away.

 

[Kamd90Chevy]

i had a similar problem, mine turned out to be the Pick-Up Coil in the dizzy. Downside is you have to take the whole thing out to replace it...but that fixed mine....till the ICM wen't out lol...that's what i get for not replacing it when i had it out and apart the 1st time