The Dragon

iTrader: (6)

Ported LS6 heads with a vindicator dual .660 springs etc.

I'm using the factory OS MAF tuned with 36 lb injectors, brand new racetronics pump, etc.

The lean condition usually occurs at light throttle, less than 12%, cruising from 2000-2600 rpm's.

BUT it doesn't happen all the time OR even often at all. My shop didn't notice the spike yet but I told them to take it out for a steady cruise o the highway and it should show up.

They already checked for leaks by the O2 sensor on the drivers-side of the Kooks 1 7/8-2" headers (it goes lean on the drivers side only)

When the incident occurs, the passenger side will read -6.x lterms while the drivers side will go +25%. Obviously the car will begin to stumble and backfire form all the fuel being dumped in. My wideband will shoot to 17 af at this time.

They checked the fuel pressure at the rails; perfectly fine.

Any suggestions?????

got-a-ls1

iTrader: (12)

could be as simple as a bad/worn out o2 sensor... id start there first. i dont know how often it shows up but if you can produce the spike in closed loop but not in open loop then you will know

The Dragon

iTrader: (6)

It only occurs at low rpm light load conditions where timing demand is significantly higher than at WOT.

That, plus the low rpm miss I was getting, and Frost's input has led me to believe the crappy MSD coils are the culprit for the perceived part-throttle miss.

I'm swapping out the coils today and see if that fixes it.

Thanks for the response!