stumble and misfire on acceleration

[ghet0skate0]

hey guys im new to these forums ive looked around some but i cant exactly find my problem yet...
i have a 93 buick century
i have a k&n filter on it
i had a new MAF put in a while back for an idle problem
then about a couple months ago i filled my gas tank up with speedway gas and it gave me some bad misfires when i would accelerate
so i went though it filled it up a couple times with some shell gas and the problem is still but not as bad as the speedway gas but its not going away... i got an oil change and now im running some fuel injector cleaner though it right now with some premium gas but im not really sure what to do now other than take it into a shop to have it checked out...i dont have any warning lights go off either it runs fine if i am at a constant speed but when i accelerate it misfires and stumbles if i accelerate quicker

 

[DailyDrifter]

Why did you put race gas in a century, were you trying to get to church quicker?

 

[Underboost]

LOL! Replace your O2 sensor & Spark Plugs. LOL!!!!!!!! You might also need a new catalytic converter.

 

[DynoTune]

By "speedway" gas, are you talking about gas from the cheap-o gas stations called "speedway", or race fuel?

 

[1chance]

If all fails, i had the same problem. It was the coil pack!