After the transmission if fully warmed up, with the transmission in neutral, and engine running, pull the dipstick that is back by the firewall and has a red top to it. Look at the condition of the tranny fluid, as well as the smell. Does it smell burned? Wipe off the dipstick, and note if there is a fair amount of black that is left behind on the rag, along with the tranny fluid. Put the dipstick back in, then pull it back out. What level is it on the dipstick?
Are you having any other issues? It could be as simple as a bad throttle position sensor.
Black 2000 SSEi, Silverstar Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, drilled 180 degree thermostat, Intense FWI, PCM, shift kit, and 3.4 Pulley. Solid front mount.