New 5ktq, new problems...

[John Forbes]

Well I finally got the new 5k. The car looks great, but unfortunately doesn't run as good as it looks. What I got is a misfire that only occurs at the verge of boost, basically every time you give enough throttle to bring the boost to the .9bar area the engine starts missing. No codes showing, and no visible problems (ie. all intake boots apear to be healthly enough, no cracks, micheling man is a bit on the soft side but not broken). I've already replaced the plugs and fuel filter with new, and the plug wires and cap with good used spares. Also tried a second ECU, but I kinda knew that wouldn't help. Fuel pressure is fine, just shy of 3.5bar when running, a tad over 4bar dead head pressure.

Stale gas was suspect, so I pumped out the tank and gave it 5 gallons of fresh 93. The old gas was a bit on the nasty side, but nothing bad enough to gum up anything.

Any ideas?

-Cody Forbes
'87 5ktq - Black beauty
'91 80 - still debating on turbo