Hey I am having trouble with my 1984 305 4 barrel in my monte carlo LS. It will run perfect if you put brand new spark plugs but about a half an hour after use of the new spark plugs it will begin to miss it will run on 8 then 7 then 6 then 5 then 4 then 3 then 2 then it wont run at all and if you take the plugs out and sand blast them it will do the same all over again. I was thinking the camshaft was gone because most cams go in 305's but if you guys have any ideas of what is going that would be great.

 

depends on what the plugs looked like when they came out before cleaning. Could be a carb dumping too much or burning oil. Most cases I have seen a bad cam usually will have a miss and possible popping at all times. Carb or fuel press problem would be my first guess without seeing plugs.

 

I would guess the carb or the oil seals.

Check the ends of the tail pipes. If you see a lot of black soot the engine's running too rich and you have a carburator problem.

One other thing that could make the engine run rich and not be the carb is the timing. Such as the timing is off or there's distributor problems.