I've seen a number of posts over time about flat spots in acceleration with a stock WBX so I'm posting this in the hope it will help someone. I've lived with a flat spot/no acceleration from a stop, especially if even a little bit uphill (needs more than minimal power to get moving) for a couple of years now. Fine when cold but after a few minutes of running and warm you step on the gas from a stop and it holds a committee meeting before finally picking up when the engine gets to about 2,000 rpm. BTW, this is with an automatic. If this were a stick I'd expect to kill the engine. Two of the best Vanagon mechanics I know of have both been stumped by this one after working on the rig and trying to figure it out. Some time back someone on one of the lists responded to a post about this problem and said that they had the same problem and it went away when they put in a new AFM. Well, I've been sitting on a virtually new (less than 1,000 miles on it) AFM for a couple of years, picked it up when Vanagon Syndrome cropped up but hadn't put the new AFM in because the 'pigtail' fixed the Syndrome and was running fine except for the problem described. Dumb move on my part, should have put the new AFM in two years ago. Because it was installed yesterday and after a little tweaking of mixture, idle and timing (to get them to spec) my Westy is running perfect!! No hesitation, no flat spots! And oh yeah, just ran it through emissions testing today, perfect. The van may actually be running better than it has since I got it just short of 10 years ago. Lesson learned was stated by someone I told about this last night: It's amazing that a 20+ year old AFM can still appear to be doing it's job right and the van is running almost perfect but that AFM is in fact bad or going bad. BTW, don't get me wrong, I'm not suggesting anyone with running problems run out and spend $500 for a new AFM. That's not going to be a cure-all for running problems, lots of other things to eliminate first. In my case, if I had had my Westy in a shop somewhere and they said "We've tried everything with not help, our guess is that you need to spend another $500 for a new AFM" I'd have told them to button it up and headed for another shop.