1996 taurus OHV 3.0. When climbing a mountain on the highway (70 mph) engine light flashes, and engine misses badly. Upon throttling back, or reaching the top, engine runs normally. ONLY happens under these conditions. Code generated is cyl 4 misfire. I have changed and or tested the injector, plug, wire, and coil.....all are fine. My friend who is a 35 year ford mechanic is stumped....swears it must be electrical. (????) Any thoughts ? Thanks in advance.