What engine does it have? V8 or 6 cyl? Has it been sitting long? Carbs. act up if they have been sitting, seals dry out accelerator pumps are sluggish. Sounds like the timing is retarded or it's running lean. Did you put fresh gas in? does it have an exhaust leak? air coming in to the pipes can cause this, but probably not. I have forgotten more about engines than I know anymore :o .
Just a WAG on my part. I am sure others will have better advice.
SBC with points: .019 or 30 degrees with the engine running, 1/8th allen wrench and a dwell meter.
Inline will be .016- .019, but I may be wrong. Should be enough to get you home, though.
