No load part throttle misfires e6x
 

have you ever had an issue with the car misfiring not under load way before it ought to?

The haltech manual suggests that under no load conditions sitting in neutral you should be able to rev the car cleanly at about 14.7AFR throughout its range. Most of what I've read on here agrees and many go leaner when cruising.

I've been trying to track down some goofy behavior my car has been exhibiting recently. I thought my TPS was mounted poorly, but I fixed that, replaced plugs, new plug wires, and the car would still studder/misfire at certain RPM points. If i held it steady at a certain RPM it would sound nasty, studder, and egt would shoot up.

Well I did some playing with the fuel maps and noticed that if I fattened the mix up this problem went away. I'd been leaning them out because the car was running on a primitive tune that pulled good at WTFO but dumped fuel everywhere else.

So without realizing I'd eventually leaned it enough that it started acting up on me, but i didn't think my fuel was a problem because this is all happening at 14.0 AFR, it's idling right now at 12.5.

I do from 12.5 at idle ramping to about 13.5 by 2500, and cruise at high 13's at 3000. It's done many highway miles without a problem, but recently I tried going into the 14's and it misfires like crazy. I was pretty sure that most people were cruising around 15.5-16, so I should be able to go much further.

If I don't go leaner than mid 13's AFR the car is smooth, but my mileage is low teens. I'm well aware that the car should run like ass at lean AFR's, but in my experience I'm not approaching those yet.

This is not a new install, it's been running for a couple years, and has proven very reliable. It had a dyno tune on the stock turbo by Ludwig. Stocker blew up so I slapped on a to4e 60 and a turbo intake (had an s5 n/a with ports/vdi wired open). ^that's all I've really done to the car so far. The tune was not finished and I've just been trying to get the driveability right, that's when this happened on me.

Could a weak spark cause it to not fire lean mixtures? I'm redoing the coil set up on the cars soon (BDC's sequential trick, with individual crane boxes for the leading) for other reasons and kind of hope that might help this issue as a side effect.