Rough Running 1968 289
 

I am totally frustrated with my 68 convertible. The engine starts fine and while cold runs smooth. Once warmed up I can't get it to run right. It sputters and misses and I have to keep pumping the gas to get it to run down the road. I've replaced the carb, coil, points, fuel pump, fuel filters, and still the same problem. I checked the timing and its at 6 BTDC.


Any thoughts. Thanks.

Mark

6? Seriously? Set it to 10-12 at least. And has the carb been tuned at all? Pulled any plugs? What do they look like? Reset the timing and see what it does, if it still runs like crap post pics of the plugs.

not sure about the timing but dirty or old plugs will kill your spark, basic troube shooting, start small work up to big. and never give up :)

Tell us more about the car. Is it stone stock, still having a points ignition system?

Sounds like a choke problem, but if he replaced the carb, maybe not... have you ever replaced the vacuum advance on the dizzy? get the timing right too, like said above.

rough running 289
 

New vacuum advance, carb tuned. Only runs rough when warmed up. Could it be a worn out timing chain?

Are you sure it's tuned? Are the plugs getting sooty after it's warmed up?

We want to help, but need more information.

4 degrees of timing isn't going to make that big of a difference. Sounds like old plug wires. A little more info would be nice though. When does it miss and sputter? Do you see any smoke?