I have a 1990 f-150 with the EFI 300 straight six. Lately, I was backing into my driveway, my motor was doing a hit and miss. Smoking heavy, loping, no power and when you stepped on the gas even a little, it shut down. I replaced the computer and it cured the problem. But now, it does it when I start it and takes a good 2-3 minutes to stop missing and carrying on(smoking, lopping, shutting down, ect). Just recently I needed to leave in an emergency and my truck left me sit in my driveway, acting like a POS but as soon as it wants to move, it's ***** to wall but I still get a random miss while I'm driving. This was going on long before I replaced my computer. I've asked my buddy's who have a 300 and they say it's a golden motor and never gave them problems but I've been having NOTHING but problems. Any words from the wise?

 

I'm having a similar problem. Mine never quits on me, however. Misses like hell right after i start it in the mornings. It all started when my crappy duralast distributor sheared off the roll pin that holds the gear onto the shaft and dropped the gear into the oil pan. Had to jack up the engine and take the oil pan off to get the gear out. Changed the oil pump and screen while i was in there. After i got it all back together, put a new distributor in, and timed it properly with a light it started missing. Since then i've replaced the battery, spark plugs, voltage regulator, positive battery cable, alternator plugs, air charge temp sensor, map sensor, egr position sensor, and had the alternator tested. Still does it. And i've found that it's worse if there is some type of electrical load. For example, if i have my headlights and heater on it misses like hell. But if i have almost everything turned off it still staggers a bit but not nearly as bad. If you figure this thing out please let me know.
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