Hi gents, I had similiar problems on my Benz which stymied me for quite awhile recently. I started having low power alot on pull out or even at cruise. I pulled tank, cleaned it, replaced screenvery bad) and filters. Things were great for awhile, then same problem again. after much pondering I checked throttle linkage. I found that after about !/3 throttle movement the cable for boost pressure from ex. manifold would jam the link on vacuum valve against heater hose. I spot tied it to an inj. line, rechecked throttle movement thru entire range, no biding. been great ever since. After cleaning cable the last time I routed the cable inside of button on alda instead of outside towards radiator. It helps when you put problems in when fixing something, ha, ha