Justhereforinfo

iTrader: (2)

I think I might have a coil acting up. It idles fine, but i have a very flat spot in my powerband at 3400 in second gear. Tires dont spin as much as they should. One of my 156kmile coil packs is loose inside the bracket. Found that odd. It ohms out the same as the others though.

I setup a vcm scanner config to log all 8 cylinders for misfires. And I'm seeing 0 all the time. not one single misfire. I find that odd, there should be some false misfires.

Now I did max out all my misfire tables since I had trouble with my aftermarket cam setting off false misfires. If I return those table to stock, I'm sure Ill start throwing the p0300 again.

what should I do?

Justhereforinfo

iTrader: (2)

So i changed the low rpm misfire table, all values to 1. I started seeing random misfires under 1000 rpms, but it sure didnt feel like a misfire. it idles really smooth. I put the medium rpm table back to stock and drove it around. No conclusive evidence that point to any coil pack in particular.

rpturbo

iTrader: (47)

So just to be clear, you just figured it was a misfire because it's got a flat spot? How you done any log files to see if maybe it's pulling timing because of a not so good tank of gas? Do you know if it has any knock retard?

I pull and sell a lot of coil packs, and very rarely find any bad, and normally when they are bad, they are bad, and I do occasionally find some that are just loose in the bracket.

joecar

When a misfire occurs, you'll get unburnt fuel/air into the exhaust, so O2S should show lean peak where the misfire occurred... may or may not be able to see it in a log depending on the duration of the misfire and the condition of the O2S.

Justhereforinfo

iTrader: (2)

Yea, i think my coils are fine. I believe i miss diagnosed the flat spot. Ill setup a new config file to scan for timing and knock retard. While i fixed my mohters lexus she was driving my truck. She did put some 7/11 87 octane in it. So you might be onto something there. I topped it off with 93 octane and a bottle of octane booster. We'll see...

Thanks for the info on the coils. They do seem to be fine.

patSS/00

iTrader: (6)

I found that when I logged misfire history for each cylinder it was alway 0, but then changed to logging total misfires and was getting a few (at idle). I figured misfire history just wasn't working in hptuners.