Just Dyno'd-need help Jeckyl

Well i finally go to a dyno and solved some problems but created others. Well the car made 338hp and 272lbs of torque @ 1.12 bar. However now there is a bad stumble when the rpm's are from 4500 to 5500 and then pretty much clears up after that. It does it whether the boost is at 14-20 lbs. A/F stays in the 12's the whole time and then the graph just shows peaks and valleys in the 12's in that RPM range. I dont know what could be causing this, but is not much fun to have a fast car that stumbles, thanks for the help.

Excellent HP! ... the torque seems low though.

How old is your ignition? (cap/rotor/wires/plugs)
Are you using Toyota parts there?
What plugs and what gap?
You referenced 20 psi ... I assume you did not dyno at that level?

1.12 bar is just under 16 psi.
Are you sure you are measuring bar?

Sorry about the typo Jekyl...it was 1.21 bar on the greddy profect, autometer read around 19psi. brand new plugs NGK 7 range, all other components are toyota around maybe year and a half old, but not many miles as the car was down around 10 months. gap i believe is either .28 or .30. Also, no i didnt dyno at 20psi just wanted to play with boost levels to see if it went away. It seems NOT AS bad on pump gas, but its still there. I hope that helps at all

If you are going to run 20 psi, I woud suggest a tighter gap .025- .026 range.
Do NOT regap the lplugs you currently have.

You just referenced pump gas ... what fuel were you tuning on?

108 unleaded....i just boosted today and it pulled very clean and hard. I did it again shortly after and the studder was back, i guess it is now an intermitant problem.

What it the reason for not re-gapping?

Once you have a plug gapped and it is run ... trying to regap it would make it very brittle. That littel electrode breaking off could destroy a piston or a valve .. or both.

Way to much risk for a plug that costs $1.75.