JAYNO20

iTrader: (2)

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?

mexi_loco

iTrader: (7)

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?

JAYNO20

iTrader: (2)

No clue, running on the OTTP stage 2 tune.

mexi_loco

iTrader: (7)

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.

JAYNO20

iTrader: (2)

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?

mexi_loco

iTrader: (7)

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.

JAYNO20

iTrader: (2)

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

mexi_loco

iTrader: (7)

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.

Redefined1

iTrader: (1)

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.

JAYNO20

iTrader: (2)

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

Redefined1

iTrader: (1)

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

mexi_loco

iTrader: (7)

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.

JAYNO20

iTrader: (2)

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?

mexi_loco

iTrader: (7)

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.

Redefined1

iTrader: (1)

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

JAYNO20

iTrader: (2)

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

Redefined1

iTrader: (1)

if your talking factory gap its around .040

mexi_loco

iTrader: (7)

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.

Redefined1

iTrader: (1)

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

mexi_loco

iTrader: (7)

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

Redefined1

iTrader: (1)

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

JAYNO20

iTrader: (2)

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.

mexi_loco

iTrader: (7)

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.

Redefined1

iTrader: (1)

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.

mexi_loco

iTrader: (7)

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.