Lately my accord has been feeling rough when revving higher, like a hesitation or something. I replaced the exhaust manifold and the exhaust system seems fine. Transmission shifts good. I’m not sure what else to do. Thoughts?
How old is the car and how many miles are on it? A clogged fuel filter could do that since the car requires a higher rate of fuel supply when the revs are higher. Also, if the spark plugs are worn out, it could cause that too. If it's a 4-cylinder Accord, you can easily pull out one of the spark plugs to inspect its condition and replace all 4 of them if they're worn out.
It’s a 1998. You think it’s possible to be the fuel pump? It only really happens on acceleration. I can check the spark plugs, but the engine idles smooth so I’m not sure entirely if that’s the case
It could certainly be the fuel pump. But, usually when the fuel pump goes bad the car will struggle to start and stay running. Try having the fuel pump pressure checked. I believe in those Accords, the fuel pump and fuel filter are a whole assembly located inside the fuel tank - there should be an access panel underneath the rear seats to get to that assembly.