350 TPI L98 needs a new o2 sensor and MAT sensor which I think is the problem but it seems to idle like its about to die really choppy and the exhaust is making like a clanking sound could be trans but not sure the trans shifts really hard and seems to not be as responsive when I gun it takes a little bit to register to go into a lower gear What do you think is causeing the problem with the exhast and trans could it be the o2 sensor or MAT with the exhast?

Thanks