Chevy 350 cuts out!

i drive a 1982 el camino with a chevy 350. i was driving down the road and all of a sudden my car cuts out and picks back up...it does this for a bit. so i drive it home call my group of car know it alls and they say check the distributer...after checking i replace the cap, rotor, and coil...still messes up...then i replace the spark plugs but notice im running rich ...so i start using 91 oct. gas ( was using 87 and friend said it would help) ...i put a better intake to add air and adjusted my chock...still messes up but now only cuts out or backfires at 1000 rpms for just what sounds like a sec...just like fine fine fine puuuu fine fine fine....WHATS NEXT...timing?

I would check the pickup in the distributor. You can unplug it and use an analog ohm meter if its working properly the dial should sweep when trying to crank the engine. They can heat up and cut out sometimes. Auto Zone or Advance can check the module free. Use a hair dryer and warm it up first I put a drop of water on them and if it starts to boil stop. I have a Mac module tester and they work fine until they get hot.

thanks for the post but it seems to not mess up when the engine gets around normal temp and hot??? im so confused

Does this vehicle have a carburetor if it does check that the choke closes then make sure the choke pull off a vacuum operated devise opens the choke
appx. 1/4 to 1/8 inch it varies so check the manual. Any way check in the carb. area.
If it has two injectors setting where the carb. used to be ohm the temperature sensor for the computer a two wire sensor. If this gets out of range it will lean out the fuel mixture.
Advance or Auto Zone will scan for codes free.