I think its one maybe 2 cylinders missing but at idle and when I give it gas it starts to miss at part throttle crtuise it seems somewhat normal. It was underpowered for a while now and after sitting for a bout a month waiting on a damn part it now missfires sometimes gives a little backfire.... Maybe coil? What does the ICM do when it goes bad? Opti was replaced a few thousand ago and I got it from Jason Cromer so its a gm unit. Also no check engine light.

 

Do you have the basics covered like plugs and wires? When I first bought my car, it had the original plugs and wires at 94000 miles. Needless to say, when I measured the gaps of the plugs, they were almost double the stock specs. and two of the plugs had some fouling which would explain the horrible performance that the car had at first.

 

The miss only started after it had been sitting for a month so plugs are pretty much ruled out and the wires are my next suspect but are well tucked away and have been in the same position with the headers for nearly 2 years and I dont think they would degrade from just sitting so Im thinking the ICM which I know nothing about or the coil but maybe something else could have happened as well I mean the right blinker blinks slow as hell now... not sure why that happened from sitting either....??????????

 

How old was the fuel before it sat for a month? Since you mention the blinker, how old is the battery? Have you load tested it yet?

 

brand new full tank of chevron premium right after I started driving it again, and the battery is a 6 month old optima red top, voltage reads fine on the gauge as well... also it was only the right blinker that slowed up.