So i have a 98 pontiac gtp 3.8. Ran fine until one day, I pulled out onto the highway and gave it gas to get up to the speed limit (55 MPH). It started jumping and every time i try to speed up now it bogs out and barely starts climbing up to speed? Dad has already replaced the fuel filter and spark plugs. Thought it might be a bad tank of gas (so he says) so i filled it up with 93 after using gas cleaner. Any ideas or suggestions? Because as of right now, I have no car for school and work. Thanks!