weeble1

iTrader: (6)

Been trying to chase down a bad miss in my motor. Motor is a Gen IV 6.0 with a LS3 top end. Fresh rebuild (bearings, rings and valves). Recent new plugs, wires, changed the 02s, swapped the MAF, checked the MAP sensor seal (LS1 MAP on LS3 intake) and swapped out to a good set of heat sink truck coils. All of this is when I was trying to track down a small miss under 3500 RPM at low throttle. I'm not sure if that miss and the new miss are related, but it the new miss started yesterday.

It seems like it only happens after it runs for a few seconds. It also seems to be spark related. I can drive down the road and it will miss regardless of RPM. It's a consistent miss that will go away for a couple seconds then come back. Like the car is running on 6 or 7 cylinders. It doesn't really feel like a random, multiple cylinder misfire, feels like it's on the same cylinder. I can put a spark light on every plug at idle and all have spark. I'm kinda lost at this point so any help would be greatly appreciated. I changed the 02 sensors last night and the problem is still there. The build has about 800-900 miles on it. It ran great prior to this and pulled hard and if you start it cold and drive it, it won't miss for a few seconds then it starts.

weeble1

iTrader: (6)

Any thoughts?

Eric Trujillo

I would check the IAC and TPS as a precaution. Did you have it tuned?

Need4Camaro

iTrader: (1)

Have you checked into the fuel injectors? how old were the injectors you used for your swap.

weeble1

iTrader: (6)

I checked those and they seem to be good. The car was tuned and still had the slight miss but this developed a couple weeks after the tune.

weeble1

iTrader: (6)

I haven't but the further I read into this, the more I seem to think it's the EV1 to EV6 adapters. I'm going to pick up some dielectric grease and see what happens. The injectors were acting fine for a couple weeks after the tune and all of a sudden, this came up. Maybe one got stuck shut? Not sure but if the dielectric doesn't fix it, I'll send them off to FIC.

weeble1

iTrader: (6)

Found a burned wire. Thought for sure that would fix the issue. I replaced it and it did nothing. Now I'm getting a P0200 code. Injector circuit open. I found one of the injector adapters with a crack in it. Not sure if that's the issue or not because it seems to still be making contact. The miss feels like it's just one cylinder. I'm starting to regret building this damn car.

Need4Camaro

iTrader: (1)

cant do that. its all apart of the hobby, the more we troubleshoot it and eventually fix it, the more it becomes apart of it.

weeble1

iTrader: (6)

Tracked it down to a defective injector adapter.

Need4Camaro

iTrader: (1)

I had a feeling it had something to do with your injectors, its the only thing ignition related that wasnt mentioned before and the only other thing that could cause a specific cylinder to miss. Let us know how it goes when you fix it.

weeble1

iTrader: (6)

So replacing the cracked adapter fixed the dead miss, but I still have a slight miss at cruising speeds and a little backfiring under 3500 rpm or so. Going to try putting a tie wrap on all of the adapters to insure they are making good contact. A buddy of mine was having a similar issue and that fixed it. Also going to swap the fuel filter. Any other ideas?