Hey guys, couldn’t find anything on this with the search bar for random misfires. But I’m currently tuned on my built LDK long block. Just changed the coil packs/spark plugs and the car keeps getting random misfires was specifically on CYL1 would go up to 10 misfires on cold start idle then when I start driving it would basically go away. Switched over to NGK LFR6A plugs 0.28 gap. Now it’s not misfiring as much on cyl 1 but now scatters through all 4 cylinders only showing 1-2 misfires. Not sure why anymore. Car recently got a smoke test, compression test and leak down. Passed all tests.

car has MAF relocate, HKS BOV, exhaust, short ram intake, upgraded intercooler, charge pipes, upgraded valve springs cams and OE fuel injectors.

any one have any thought what else I can look into so I can get rid of this misfire? Seems like under wot there is 0 misfire and no spark blowout.

thanks!

 

whats your stft and ltft at closed loop and open loop? sounds like a wideband o2 goin bad. shouldnt even notice somethings wrong with only 10 misfires

 

I’m really not sure as I don’t have a hp tuner to do the logs unfortunately... so you mean the o2 on my exhaust?

 

have you tried a CASE relearn since swapping motors?

 

correct me if I’m wrong but I thought you couldn’t do CASE relearned on these cars?

 

I don't know, maybe?

 

You cant with the lnf/ldk

 

oh well. i just know i need to on my le5 to hopefully solve my random misfire code.

 

go back to the stock plugs AC Delco 41-108 and set the gap at 0.030" you shouldn't need to run a 0.028" gap unless you're running a 50lb/min or larger turbo and then only tighten the gap for high RPM blowout.