I pulled my Afms out at one stage when my R34 was playing up, saw the thread on soldering, opened them up. To my great satisfaction there were dry joints, thought to myself "yip, Nailed it". Anyway, soldering it didn't fix the stumbling issues I was having while driving. To cut a long story short. Sometimes AFMs are stuffed, sometimes intermittently. Be careful of swapping another used set in because the replacement set might be even older than the ones you are taking out. Could it still be the AFMs? Im running a map sensor now because I got driven insane by AFMs.