I now have another issue with my 99' Blazer. I attached 3 videos to show what the Blazer is doing. It's hard to start sometimes and when it does start it idles rough and seems to misfire. When I hit the throttle quick it wants to die but if I rev up slowly it runs fine. That to me is usually a fuel delivery related issue. I checked fuel pressure and it seems fine. (In video also) Anyone know why this is happening? It JUST started happening.

 

Its had an issue with starting where when it's not full charged it will turn over and sputter a little. When fully charged it will start but start hard. Battery tests good with a load on it. Security light is always on but it doesn't seem to change whether it will start or not.

 

Well I got no responses but i think I have identified the problem. I was screwing around with looking for the parasitic draw or whatever it's called and I was messing with the fuse for the Body control module the TBC or something and I got my security light to stop staying on the whole time and goes on and off like it should now. (I think) I decided to unplug the MAF and lo and behold the idle smoothed out. Plug it back in and restarted the truck and the rough crap idle with sputtering was back. Unplugged it and gone again, restarted with MAF unplugged and and still gone. I think I found my issue. Just need to clean/replace this one to find out for sure. This one is pretty clean but who knows whats going on with those tiny wires going across the insides.