With the oil problem he's having it might have an oil coating on the plugs causing the missfire, good point.

How's the fuel pressure at that range? Possible valve float?

 

I doubt it's valve float, my springs are good to like .65" lift and I'm only running .600, and it happens at lower RPM's too. FP is good, probably about 65 psi. Oil burning seems to only be an issue at idle, but I still haven't figured that problem out.

 

The timing is too low.So change the plugs and put timing around 18degree's for 6lbs of boost.Too little timing can bog an engine.

Also,I'm expecting this is tuned 2 bar SD?

 

Yeah, 2bar OLSD. I was running 15* before and it was missing too, I guess I can try to run 18* but it seemed to get a little better when I pulled more timing.

 

If you want you can shoot me the tune and a log file.I will look at it and see if anything sticks out. slowhawk@comcast.net.
I've found many hiden problems in tuning in the past.Maybe you have one that I'll notice.

 

I just sent you an email. One thing I just noticed (I put this in the email too) is that I had a rich spike to about 10.2:1 right where the hesitation started. I need to pull some fuel out there and see if that helps at all.

 

I am still having the same problem you are. I pulled the plugs and re-gapped them to .024" as was suggested to me by my tuner, and nothing changed. The MAF is not getting wet from the alky as was suggested by someone else (I know you are SD). I was thinking of going speed density this spring because of the advantages in the fuel tuning, and I was hoping that that would be a solution, but perhaps not. My engine is stock, 8000 miles, and I run 8lbs. I have heard the stock wires can be a problem, but in the end you could chase your tail all day with this kind of problem. If I find out what mine is doing I will instantly post here to try to help you out. Some of the others on here are more experienced than me, but I am in the same boat as you. I know that under real world driving my truck fell flat on its face at around 3lbs untill he put timing back in it, but no stutter. I went back into "reduced engine power" the other day, and this is after he raised the corresponding tables. So I need to find time to throw at it, maybe this week. I see the same stutter at the same time as you, above 5lbs. I hope to figure this thing out soon!!!! Good luck!

 

By the way, are you getting any codes? I keep getting a P0300 multiple misfire. I will hopefully get to drive it with the scanner hooked up tomorrow to watch the individual cylinders in reference to boost and see at exactly what point it starts to stutter.

 

I'm not getting any misfire codes. In 4th gear it starts to miss around 8-9 psi, and in 3rd it starts to miss around 7-8.

 

If you are not throwing any codes, your plugs and wires are OK, you got sufficient fuel pressure, injectors and AFR are OK, - could this be a transmission problem. I had problem similar after screwing with shift points on the tranny. It felt like a miss but was actually the shift point set incorrectly.