stumped

[Mike Miller]

I've been chasing a bad miss problem for a while. I seems to be getting 
worse. Spark plugs  all look good and I've swapped out the wires. I've 
replaced the MAF and ECU (now stock) and have no vacuum leaks. I can make 
full boost according to the dash gauge and I can hit high RPMs. (6000+). The 
car runs smoother above 3k rpm. I am getting 1.6 boost at about 1/8th 
throttle and can make the boost jump in neutral up to 1.1 (.8 is normal for 
my altitude (4800ft) with the engine off/ingntion on).

At slight throttle, there is a steady miss that magnifies as the throttle is 
increased. The miss is worse the higher the gear. There is no miss when the 
throttle is lifted. Initially, as long as I kept boost under 1.0, it ran 
fine but now it is missing even at .8 bar.

I'm wondering if the Cat is clogged - thoughts?? That might explain the 
abnormally high boost with very little throttle. It holds about 1.6/1.7 from 
about 1/8th throttle clear to about 7/8ths (don't feel any acceleration 
change) - WOT will then push it up to 1.8.

mike