Current set up thats in the sig. Well my car seems to idle with a slight miss every now and then, maybe 1-2 times every 5 seconds. Also when im cruising up to speed at very light throttle it will kinda miss/stubble, but give it a bit more gas and it will still not sound smooth but will jump right up to speed. Pretty much brand new MSD HEI, and a new set of wires and plugs put on last week. Before it was a wire or two arching, that I could see at night. The wires/plugs didnt do anything for the miss.

I did redo my valve lash and it smoothed out alot, but after 10min it came back. I went out and bought some poly lock nuts for the rockers to make sure they are not backing off. When I set them i thought a few felt a little too easy to turn. But the way the miss feels when cruising its not happening every time on the same cylender, more like it will fire ok a few times, then not.

Timing is set at 12* int, and 34-35 total, plus another 12 with vacuum advance. Could it be the vacuum advance? There are no vacuum leaks, Ive checked 4-5 times, and hose clamped every connection I could. Vacuum does jump around at idle from 12-15.

I thought the carb could be off, or possibly too lean, so a carb calibration kit is in the mail. The plugs look new still, with a tiny bit of tan on one side, and thats after 200 miles. Gas milage is crappy too, some where around 5-7 in the city and 10-12 on the highway.

 

Well I dont know if its the ignition or not. I did the unplug each plug wire to find the one that doenst make a difference, and everyone I unplugged didnt seem to effect the engine at all. I got a small drop in RPMs from taking off #2 but didnt notice anything on the other wires.

 

im having the same problem ive changed everything u did and it didnt fix the miss hope someone can help us out