I'm beating myself up here.My 75 L82 runs great,and seldom gives me any problems,but the other day it was like it is loaded up when i am driving.it idles fine,and revs fine from under the hood,but when you are driving it is like it is loaded up,and chugging when you put it under power.You can get it up to cruisig speed,and she is smooth,but the second that you try to give it more gas....same thing.
So far,I have.....
pulled a few plugs,and the burn pattern is fine.I changed all the plug wires with some good MSD wires laying around,and ran/idled smoother,but still the same thing under power.I pulled the quadrajet,and pulled it apart,and blew all the passages out,and still the same problem.I also,pulled the fuel line to test the mechanical pump,and pumped about a quart out before the float bowl ran out.
????????
My friend told me to look at the pick up wires at the dist,and look there,so tackling that later after church.
Any suggestions would be appreciated.Kinda frustrating,cause this is a car that I would have no hesitation to drive cross country.I beat on this thing pretty hard,and hoping I didn't jump a tooth on the timing chain.It just happened all of a sudden tho.
HELP!!!!
Thanks guys!
Kevin

 

Have a good look at your fuel venting, tank, canister.

Check the ignition mechanical, vacuum advance.