I seem to be having driviablity problems with my 91 940T. It all started with what I thought was a plugged fuel filter. The car would loose power about 4,000 rpm almost like it was hitting some sorta of rev limiter, it would loose power but if you kept it floored it would drop down to 3500-3200 rpms and then acceralate up agian. Changed the fuel filter and now its a lil better. I dont get the loss of power like before. Now I get it when I'm doing like 85 or so and I floor it. It seems to only happen if the motor has to hang around 5000 rpm for a long period of time. But still same thing, acts like its hitting some sorda of rev limiter and it dies down to like 4000 rpms and picks up agian, if I was to hold the pedal to the floor it gradually loses rpms, to the point of it doing this bucking at 3000 rpms then dropping down to 2500 and accelerating. Overrall the car is sluggish and just feels like its not peppy anymore. Fuel filter has been changed and airfilter. The CAT has never been changed but I was wondering is this a charateristic of a plugged CAT??