Computer Problem?
 

So after I put in new sparkplugs in the day before yesterday on the '79 Cordoba I drove it around and it seemed ok other than the car rattled a bit with the engine on. I switched seats with my dad and when he drove it the car started having occasional misfires. Today he drove it to get it emissions tested due to new laws and he said it still had misfires(didn't get emissions due to the wait). Monday we are taking it to a place for a tune up but today I have been reading that the Lean Burn System that is on it was never any good and that it controls the timing of the engine. Is there any way of checking it or anything I can do? http://www.allpar.com/mopar/lean-burn.html

how did it run BEFORE you did anything to it?

Doesn't sound like an ignition type problem to me. Could be A/F ratio got off if you messed with the carb ( i think i remember you saying you cleaned it out or something)

Did you gap the plugs to spec?

Yes I gaped all the plugs to .035 like the box said. I sprayed carb cleaner on it, found out the computer has to be hooked up for it to run(without it the car only turns over) then ran it. Never messed with any adjustments as I do not know anything about that. Car starts instantly the idle sort of fluctuates until you rev it a couple of times then settles at around 750rpm according to the tach. missing occurs after like 1,500-2,000 rpm.

Before messing with it, when driving it around it was real quiet and smooth though it felt underpowered and when you floored it it would stall. After messing with it there is no more stall or hesitation but now there is the heavy vibration and now missing.