My 305 makes a pop pop popping noise after it warms up and i tap my gas. It lugs the engine at times, then after that starts there is a knocking noise, like valves or lifters. If possible could you help me solve this problem. I will answer any question about it that what to know.
Thanks.

 

Is the noise from the intake or exhaust?

 

the sound comes from the intake, like it's suckin too much air from somewhere. It's almost like it's going to backfire but it never does.

 

Is it driveable or not? Do you mean only under hvy throttle or all the time? You might want to list the year and the type of fuel system. TBI, TPI or carb?

 

it's an '85 RS Body, with a carbed 305 Q-jet. The noise only happens after i have gotten the temp up to 190. After i get it that high, the motor starts with the popping noise when ever i touch the throttle. It doesn't have to be heavy it just has to be touched. It gets louder the harder you push it. I have 1 vacume nozzle on the carb, that i have no idea if it was plugged or not, that is open, it sucks air. I also have one on the top of the driverside valve cover that has a T line where one of the sides is open, it sucks air as well. I have tried adjusting the timing in different ways but not change, just new noises. My carb is adjusted with a 50/50 ratio at 2 1/2 turns each. Anything else I should add?

 

If you get a book on that year model it will tell you where those vac line should go. No they shouldn't suck air, plug them off or found out where they need to go. That might solve some of your problems.[8D][8D]