1996 130 hp mid-range problem

[kjdunne]

New to me 1996 model E130TXAD, 90 degree V4 looper. I can't clear up a problem between 3500 & 4000 rpm. It shudders, shakes and misses, acts like it's starving for fuel or bad lean sneezes. I've cleaned and rebuilt the carbs and throttle bodies, rebuilt the fuel side of the VRO pump, changed fuel filters, verified no air leaks in fuel line, fresh fuel, etc. Pumping the primer bulb or engaging the electric primer makes no difference. I've also checked compression, 140 - 145 all cyls. Good 7/16" spark all cyls., did link & sync per OEM manual, set timing. This engine starts easy and idles well, runs fine up to about 3400 rpm, then it acts up until I throttle up to about 4000 and it runs fine up to WOT 5600 rpm, will cruise all day at 4200 - 4500 nice and smooth. It does the same thing throttling down from higher rpms, when I get below 4000 it runs like crap til below 3500, then its OK. On a hole shot, it seems to accelerate thru the trouble range without problem. I'm stumped. Is this the rpm range of the carbs intermediate circuit? I've been told the air bleed orifices may be the culprit, they are the factory .030 ones. What else should I be looking for? Anyone have / had a similar problem they fixed? Thanks in advance for your input.