car started surging and stumbling on accel surges real bad above 2500..just cuts out.totally then recovers ..seems to run ok under light load or coast..first time i pulled the code it was 34..cant seem to find any vac leaks..reset..now light comes on when it runs bad but has no codes?..pickup in the distributor?..any ideas...this is in a 57 chevy with 86 tpi..thanks madmax

 

Fuel pressure, base timing, TPS/IAC sensors would be good places to start. Maybe you can detail this a little more, like, how old and what condition is the plugs, cap, rotor, ignition module? When it runs does it run rich/lean? Do the plugs give you any clue as to a rich/lean condition? Pretty much a stab in the dark until these things are checked.

 

it seems that when it acts up it almost like it completely shuts off for a split second..plugs look good..i will check tps ..it really isnt a stumble it actualy just shuts off.almost..worse after it warms up worse at higher rpm's..light flickers on but no codes?..i'm still thinking it might be the distr. pick up..all this set up comes of of a 86 iroc..cap rotor module wires plugs fuell pump about a yr old..i had it to the track last week then it started all this

 

Ok, sounds flakey for sure. I would check the TPS for grins, base timing, then all ignition connections. Might have a loose connection somewhere.

 

tps ok, all connectiuons are ok?