so a brief overview of what is happening is that I did an engine swap because the engine i had was making strange scary noises and it was just as much to replace with a used motor as it would be to rebuild so anyway the motor is a 1983 motor recently rebuilt with about 45000 miles on it which is much less then the motor i took out which had 166000 miles on it. in addition the new motor has headers and had an upgraded ignition which i removed and put the stock ignition back on hoping it would fix the problem.
so the misses are seemingly random although i know its electrical in nature because the gauge spikes and dips every time it misses. a while back i traces the problem with an oscilloscope to the pick-ups on the distributor which i swapped out along with the vacuum advance solenoid. then for about a week it ran perfect then randomly a week later it was back to how it was missing low idle dyeing in turn lanes you know what i mean. its gotten so bad we had to borrow a vehicle and not drive the Jeep. and the miss is not consistent its not once a revolution or within any particular period it just happens and it sputters and dies.
what ive already tried
i am putting this because these are the things everyone always tells me and ive been through it tons of times already.
this is becoming a serious issue
- check and replace spark plugs
- replaced pick ups with good ones
- checked timing
- checked plug wires and replaced with known good ones
- ruled out valves because they just had a 3-point valve job
- ruled out piston rings because of recent rebuild
- many other basic things including having a mechanic look at it which dident help at all
- replaced a special vacuum part which made a huge improvement on kicking up the idle when cold
this vehicle is supposed to be a daily driver if this keeps up without us finding a fix we may either have to put the old motor back or sell it.
thanks in advance for any help and all advice will be helpful