Q&A

Could be bad gas (water in tank possibly) and will go away after its run though the system. But the initial list of things to do would include: replace air filter if dirty, clean the throtle body, clean the mass airflow sensor (MAF) or replace the mass air flow sensor if its got > 100,000 miles on it. Replace the spark plugs if they are old. All of these things are simple and inexpensive to do yourself (or find someone who works on cars). You can get new MAF on ebay for $60, easy to replace, new spark plugs for $10-$15, air filter from walmart for less than $10.

There are so many things it could be, however. If the above doen't help, replace the O2 sensors. If that doesn't do it, you have a more serious and costly problem. It could be the fuel filter, fuel pump, or fuel injectors, but don't panic, just start with the basics listed at the top.

ANSWER #1 seems correct. Just wondering how the airflow is coming out of the tail pipe or exhaust pipe. Is it smooth, or choppy and rough. If it is rough it could be catalytic converter and sometimes you can smell a rotten egg smell. It could also have to do with some internal parts of the engine. Do you see any color smoke coming out of exhaust pipe?