My car is having random misfires, all cylinders, no check engine lights, plugs are good. I had my car on a scope and we can figure out what it is, flushed the fuel system with cleaner thought maybe a valve was sticking. didn't work any ideas?

 

Plugs or fuel. If there's no check engine light, how do you know it's misfiring?

 

Probably has Interceptors installed. You can read misfires on them.

 

Because I can hear it and we had it on a scope in my friends shop

 

This always happen to me but i would get misfires and 1 code P0172(I Think) System to rich. Turns out all of my coils were bad. But after the dealer switched them i have had no problems since

 

mine misfires all day long, idk why. No CEL or anything.

 

im just started doing it to its the coil packs mines cyl 2 lol i cant even put it under a load and gl with hills

 

My old car did this too, very random and never enough to set a code. You could hear it at idle but never under load. I logged alot of miles with a tech2 and the only times it happened were at idle or when blipping the throttle when downshifting . We chalked it up to the stage tune , it never really caused any problems except being annoying.

 

thats what mine does, when down shifting or at low rpms my interceptor either says 2 or 4 misfires....

 

Same on my 2.4sc. I was getting 2, 4 or 6 usually, at idle and downshifting with my 3.3 pulley. Funny thing was when I dropped from 3.3 to 3.0 pulley, we street tuned for the new pulley, injectors, etc, with HPtuners and the whole time only saw 1 or 2 random misfires . Finished up, plugged back in the interceptor, drove around and it showed 2-6 randomly again, right after HPtuners showed only 1 or 2 the whole time tuning. Never could feel it though, and it seems pretty common on here. Thought that was odd....

 

Coil packs are like $70.00 each though, know anywhere a guy can get a deal?

 

$41.03 each at gmpartsdirect. Plus shipping obv...

 

got my coil pack today advance for 47 the dealer wanted 89!!?

 

can hear mine too at idle. shes fine driving though other than maybe a hiccup here and there.

 

Almost all moded cobalt lsj's have a random cylinder misfire issue thats really hard to get rid of. I suggest if you have hptuners to add "short pulse" adders to your injectors.If you dont have hptuners then take it to a tuning shop and have them do this for you and they should be able to stabilize it. I do assume that your misfires are higher at idle and lesser under load? If so then this should fix your issue drastically.