So when you take off it has high rpms for ex 3000 at ten mph and it slowly gains speed then it finally catches up but you can shift again and it takes a while to get up to speed again. No grinding of gears and then if you try and and gas it to get to speed the rpms just keep going higher. Changed the tps and still didnt work. Thought it could be the clutch or flywheel?
Manual transmission? Yes. It could be the clutch. Might need adjustment. Might need replacement. If there is an inspection cover, remove it and check the clutch disc. It could also be a pressure plate with weak pressure on the clutch disc.