ok i have a chevy 350 its carbed and has accel disttrubter, i was going to set the timing last night when i noticed this, i hit the harmonic balancer with the light and noticed that the numbers were lining up with the timing tab then all of a sudden the would jump and then come back down to the same spot and do it again now ive never used a timing light i just figuered i would give it a try but i dont think its supposed to do this?

 

if the motor shakes when younotice the jump in timing then its the engine missing.

 

est,vacuum or mechanical advance is moving it

 

Or the timing light is picking up a signal from another cylinder.

 

well the distrubuter is really old and its got a biiger cam with a 443 in 440 ex lift i thought maybe it was the distrbuter and ive checked for all vaccum leaks there isnt any, ive been having problems with it because i cant seem to get it timed right and the car lacks tons of power and when u open throttle to fast the car dies what coiuld this be caused from and im running just a stock torque converter.

 

if it is carburated, it could just be cold other than that, i don't know, thats the best i can come up with. lol

 

Replace the cap, rotor & wires. Most likely you're leaking spark from one of those sources. Since it's down on power, might as well replace the plugs while you're at it.

 

could a module made in the dist to run off the computer be causing it if i dont have a computer anymore.