Ford Repair: truck chuggs, cylinder misfire, lean condition

Question
truck chuggs at low end and jerks .unles i slip the clutch and rev it up.also seems to make a valve rattle when acclerating at high end.changed the idle air control egr valve etc, 1990 pickup 351 f.i.

Answer
Hi Dan,
     Sounds like you've got a multiple cylinder misfire, or a severe lean condition. The fact that you can rev it to clean it out tells me that is more likely ignition system related. That rattling you are hearing is probably pre-ignition, which makes two pointers that maybe the ignition timing is way over-advanced. Check that first, and set to 10 degrees with the little plastic plug out (usually by the dist.). Good luck! Shaun.