I keep getting a random misfire, my current plug gap is at 0.32, should I increase it or decrease it to help prevent the random misfire?

 

you might have a vacuum leak somewhere. That's the correct gap, so my guess would be to check for leaks. What do your fuel trims look like?

 

No clue, running on the OTTP stage 2 tune.

 

Do you have access to HPT? If so, datalog it, and pay attention to the fuel trims. That should help you out. But I still say you have a vacuum leak.

 

I will most likely be getting the Stage 3 kit soon, at which point I will be getting a custom tune so if its the tune it should be fixed then...


But where should I start looking for a vacuum leak?

 

check any hoses that looked chafe or cracked. Get some brake cleaner and get spraying! I'm not suggesting it's your tune either, but fuel trims can help you determine if you have a leak or not.

 

I am only getting this misfire every once and a while... maybe once a week. Could it still be a vacuum leak?

 

it could be a small leak. That's why I say to check your fuel trims. There's two kinds of misfires (lean and rich). Lean misfires are usually vacuum leaks. The only other recommendation I have is to pull your spark plugs and see what they look like. Those are good indicators of what's happening in your combustion chamber.

 

i use soapy water to check for leaks. Also every car is different if .032 doesnt work for you trying going .035. I dont believe going lower then .032 will work.

 

Plugs are pretty black. I was told that is because of running rich.

 

is the tip of the plug black or is it the threading of the plug black?

 

I had mine at .035. Way to much. Anywhere between .029 and .032 is spec for our cars.

replace the spark plugs with some NGK's. Make sure you gap them though, and monitor what happens to those.

 

umm... I am pretty sure it's just the threading... I haven't looked in a while though.



Where can I get the one step colder NGK's?

 

chances are you may have a fouled plug, or the gap is too big. If that doesn't work, then you can always check for leaks and stuff.

 

if the tip isnt black then its not running rich

online, try ottp or cobalt-addiction or something. you can order it at a parts store. part is bkr7e

 

I have some of the one step colder autolite plugs, are the NGK's really any better?

 

if your talking factory gap its around .040

 

Get some NGK BKR6E's. Stock number is 6962. They're like less than 10 bucks. It's came in my ride, so no need to put anything else.

 

i used autolites and i had misfires. the ngks are great.

 

is that for all cobalts or just a certain displacement? Cause I could have sworn spec for our ride is .029 - .032. AUTOLITES SUCK!

 

i dont know if the 6 was a typo but bkr7e is the right part for 1 step colder

.040 is stock gap for the lsj, i dont know about the other motors

 

Hmmm... Maybe the Autolites are causing it then. I think I will switch to NGK's and gap them at 0.30 and see what that does.

 

All I know is that I have a set of 8 dollar NGK's in my car, gapped at .032 and my car is running beautifully. I used to have some 1 step colder, but didn't notice a difference performance-wise. Even after datalogging, I didn't notice any difference between the two plugs.

 

i dont believe the step colder does anything for performance. i believe it has some affect of running a little cooler. i could be completely wrong on this and someone might step in and help on the subject of 1 step colder plugs.

 

I don't think so. I believe 1-step colder means it will fire at an earlier degree than a n/a engine because more air is coming into the engine. Or something like that. It really has nothing to do helping the engine run cooler.