1984 Mustang 5.0 engine problems, engine "lurching"

84Stang5.0 · 10-02-2007

1984 Mustang 5.0 GT hatchback 5-speed. When driving in any gear keeping at a certain speed car will "lurch" as if it's not getting enough fuel, but car runs fine under acceleration and idels fine. It only "acts up" when maintaing speeds. It runs smoother when the engine is cold and persits to get worse as the car warms up. It has good fuel, fuel filter is good, carb was rebuilt prof. last year. Plugs are good, air/fuel is bang on. Stock engine and car, no mods. Thinking something to do with timing maybe? Stuck for answers.

Please Help!
-Thanks

**EagleAutosports** · 10-02-2007

Hiya and welcome. Glad you joined us, I see this is your first post.
I'd be checking for vacuum leaks, since it gets worse as it heats up. A gasket can be sealed when it's cold, and when things expand, reveal a leak.