Ok... this is still the '97 F150 4.6 adventure of trying to determinge the cause of a mis / rough performance. Brownie - tried the misting bottle to see if any arc was being thrown. No arcs. The engine starts a mis at about 25 mph to 30 mph. It shows up more readily if we are climbing an incline road. Also, as we road tested it tonight getting on the Interstate, at 55 to 60 mph, it really runs rough + the check engine lite came on. I am wondering if the throttle position sensor and the sensor that thinks the truck is overheating (so it shuts down 4 cylinders) are going / gone bad. Any ideas ? Also, we took the truck by Autozone tonight and hooked up to their diagnostics. It said that our #1 cylinder was mis-firing. Anything look familiar to anyone ???

 

This sounds like the exact same thing mine did. Only the code on mine was cyl # 2. Check your sparkplug & the wire. I would just about bet that you can see a arc line in the sparkplug boot. This is hard to see once you see it ,it is very noticeable. Anyway I put just that wire on. Well I kept having problems. Seems once you have a plug wire problem you might as well replace them all. I replaced all the wires & plugs & it ran great. Good plug wires are expensive. I would look for evidence of arcing inside the plug boot or down the side of the plug would look like a black line. The mist test would likely not show this arc. You could always change that plug/wire to another cylinder & see if the miss moves to that cylinder. There is also a possibility of a fuel injector problem. I would say it is in a plug or wire though. Even if you have put new ones on I would still check this.