Sounds like a boost leak to me.

 

Maybe it's because I haven't sent my ecu to be flashed by Vishnu yet.

 

My car did the exact same thing and rarely threw the infamous PO300 code. It ended up being the hyper active knock sensor picking up a harmonic from the trans in 3rd and 4th gears since they are on the same shaft right around that same RPM and pulling timing thinking it was detonation.

If you really wind it out in second and shift into third above that RPM does it pull fine through third? I'm not saying you have the same problem I had. It just sounds very similar and I'm curious.

 

I'll have to try, it doesn't do it all the time though, and it does it the most on colder days which makes me think boost

 

If it only does it on cold days and not religiously it is not the problem I had. You're probably right in thinking it is overboosting.

 

Put in BPR8ES spark plugs gap them at .22 or so and youll be fine trust me....

 

You are correct. Too much boost. As we know, fuel cut results in an instantaneous loss of fuel and spark. IIRC, the triggers for fuel cut are 1700 Hz Karman value at 20°C and 1000 mbar atmospheric pressure approx. That is roughly 1.2 bars relative boost.

I'm not sure how the Xede intereacts with these limitations, but there's a very high chance that this is the issue...

 

It is the spark plugs. Just go buy some NGK BPR7ES spark plugs and install them. They cost like $1.78 each. It takes like 15 minutes to install them. You will be amazed how much better it runs. Take a good look at the spark plugs you pull out, the ceramic insulator around the center electrode will have several cracks in it, on every plug...

 

Put in the plugs still does it. So overboost or exhaust flow backing up????

 

im having the exact same problem, once i get into boost it looks like it spikes then breaks up REAL bad... changed plugs got a little better, lowered mbc all the way down (running 16ish pounds) and it ran like butter... raised it back up to 18ish and it started spiking and breaking up again. Much worse in the cold.

 

Mine does the same and I am runnign AEM. Still cant figure out what the he.. going on. it does it only in 5th gear at about 18PSI stuters like crazy. any ideas?

 

Correct, your hitting fuel/boost cut. A misfire does not feel like "hitting a wall" only a fuel/boost cut have that feeling. You need to send them your ECU or you will continue to have these problems.

 

I'm having the same problem with the cold weather. Except I get it when I'm boosting through 2nd, 3rd and 4th. I'm Running the Unos MBC, I put the light spring in it and it still has the problem. I'll be changing out the plugs tomorrow to see if this helps.

 

bump for some help...

 

Replace And Properly Gap The Plugs!