Hmmm that's a hard one and after all the other replies I am reticent to suggest this, but....valve springs? hahaha. I had same issues before my final tune, mentioned it to XFT and the current tune it almost never happens on. Seems worst if the car was driven a bit, off for 15-30 mins then I drive it again and give it stick. Feels like it's got lumpy as f*k cam in it when I stop at lights. I have a set of nizpro springs to go in if it gets bad enough.

Serious!? I have had heavy duty ones put in from my tuner -.- awesome

I had the valve springs done by my tuner and they only lasted 12 months , I have the same problem now with the car running rough after a boost run. going to change the springs myself this time so I know what is in the motor.

Hi folks

what IS valve float? what exactly happens?

To put it simply the springs aren't strong enough to shut the valves when the cam Is suppose to. So they can stay open on all strokes sometimes. You get blow through. No compression or ignition. If it happens too many times you can loose a collet or both collets and drop the valve ( engine rebuild )

Makes sense to me if the engine is at high revs with full boost, like valve bounce? But what causes rough running after the revs & boost drop?

Cheers

Chris

Okay so at first I thought it was coil packs again, and I was playing around with them, I didn't think to check my dtcs so I did and I had a b and c coil fault from when I played with them.

Iv since cleared the dtcs and it's hasn't seemed to have do e it since, I dunno if it's maybe coincidence?

But could having the dtcs there cause it to maybe do this or defs v springs ?