utc_pyro Posted June 22, 2018 Share Posted June 22, 2018 Ok, this one has me pulling my hair out. At peak load, the car is jerking/shuddering intermediately. This is sometimes accompanied pops and puffs of black smoke out the exhaust, but NO changes in wide-band O2 reading like one would expect for a misfire/afterfire. It does show up on the roughness monitors though, and seems isolated to cylinder 1 and 3. Problems started after installing a Grimmspeed intake and going through MAF and load comp tuning. More specifically during day two of WOT MAF tuning it did it when I had overcorrected by 7% and it was pig rich. Sence then it's gradually started to happen more often. As of tonight when I went looking for it, it's doing it every wot pull above 1st gear. Relevant mods: Fresh-ish Shortblock (10K miles) Rebuilt heads BNR EVO3 16G Turbo ID1050X Injectors Radium fuel rail and pulse dampers (three) TGV Deleats Grimmspeed TMIC Grimmspeed Intake Tomei ELH AEM Wideband Failsafe Gauge So what would cause a missfire/afterfiare on two cylinders only at high load, but not show up on the wideband?romraiderlog_20180621_211257.csvromraiderlog_20180621_210724.csv Link to comment Share on other sites More sharing options...
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