Hello, I have a 1999 Chevy Tahoe and the other day I drove it to town and it started acting funny. It started idling rough, sputtering, tried extra hard to get up a hill. I did some research online and found that it may be my fuel filter or fuel pump. The fuel pump is engaging when the key is turned forward. Changed out the fuel filter, still the same results. I did some more research and found something that said it might be misfiring and might have to possibly change out plugs and wires. Any advice on what this could be and if I should change out the plugs?