just picked up a super clean 86 gl wagon.was over heating but a radiator fixed that.the problem now it it seems like it has some sort of fuel issue.just cruising around it stumbles alot.if i get on it hard it has great power.so im not sure if its fuel or a spark problem.it has a new tune up but the guy that had it used cheap stuff.had ac delco plugs and i replaced them with NGK.the carb is a new rebuilt one.all the vacume lines are hooked up.i plan to do an ej swap soon but would like to drive this around till i have all the parts.any help would be awesome.thanx!

are you running the stock air cleaner? if so there is a thermo valve on the air cleaner bottom. Mine would run fine until it got warm. This thing would open up and cause a huge vacuum leak. Just plug it. 

Throw away the factory carb setup and get a Weber. 

 

GD