It started at 60 mph one day and has progressively gotten worse until now, I cant get above 40 mph. Ive replaced the fuel filter, fuel pump, plugs, wires, cap and rotor, and bypassed the egr with no results.

The engine will suddenly start bucking, while making a bad sputtering noise, lose all power, and if I apply too much throttle try to die. Downshifting doesnt help, and it doesnt appear rpm related. Sometimes if it sits for two or three days it takes forever to start and it will occasionally fire and immediately die. After several attempts it will fire up and run fine... Until it warms up and I decide to use the interstate.

Engine was rebuilt months ago, and has run great since them. The carburetor needs rebuilt and I am beginning to suspect it as the culprit. I havent touched the timing since Ive had it up and running.

Any thoughts are appreciated!

 

Mine did that until I rebuilt the Carb fully. Tear it down and clean all the nooks and crannies. Use an empty egg crate to put the parts in as you go. Takes about an hour.

 

Does it still have a cat on it? if so, it might also be that as well.

 

No cat, and Ive rebuilt a few carbs in my day. It was running fine after the engine rebuild so I didnt mess with the carb. I do have a spare carb I was told was 'good' will throw it on and rebuild this carb. Hopefully my spare will get me by...

 

Swapped the carb and the issue went away.

 

I'm having a similar problem with my '84. I put on a new Weber and it was running fine until this afternoon! Doing the same as lokrix's, kinda chugging and back firing. I did take off the cat and put a straight pipe to a flowmaster, could that be the problem? Any thoughts would be great!

 

vacuum advance on the distributor could be bad?

 

Yeah, I was thinking about that... Thats about a $130 part, so I was trying to avoid that. Maybe I'll just bite the bullet and replace it. Thanks.

 

well you can check yours before you replace it. i know for sure mine is bad