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Do you have a manual or automatic transmission?
The surging engine and lack of power would indicate a lean condition. Probably not bad gas, but I would suggest replacing the fuel filter. If it is clogged, it may drive pretty normal until it is under load and really requires loads of fuel. If a plugged filter impedes the flow of fuel, you will experience a loss of power under load and surging at times. It may also be a failing fuel pump or a serious vacuum leak. I'd replace the filter no matter what. Second, I would test the fuel pressure at idle and under load.
For sure, Have a great day and please feel free to ask any questions you may have in the he future.