car idle will not hold steady. Will not accelerate over 30 miles per hour;

Possible clogged catalytic converter or restrictive fuel filter ,don't Know history or miles??

Does it miss really bad. Not running one all cylinders, possible coil issue.

Should be easy for a tech to figure out in 30 minutes. Likely are collapsed cat converter/exhaust pipe or faulty ignition coils or ignition module. Is it up shifting, if an automatic. IF not a possibly failed modulator on trans could be problem. When you post a question, the more information you post, ie mileage, transmission type, any previous diagnosis, can help and will get you more and more accurate responses.