Hesitation or slight bucking when shifting from 2nd-3rd.

can you adjust your clutch on this car if it is a stick what is it , you have to be more specific on make and model etc stick shift car or auto , usally when a car hesitates has nothing to do with the trans ,has to do with a tune up ,,

Lucas transmission additive helps free up sticky valves and renews seals Costs about 10 bucks. worth trying.

that should be a 700R4. probably a broken sunshell inside the tranny. need to have it rebuilt. Mine only cost 250 bucks for the parts, but the tranny guy is family.

a number of issues. Tcc regulator bore worn out, the infamous check ball seat it hammered badly, or/and calibration issues. I have seen all three issues on the same trans - often!

First-NEVER add anything to an automatic trans.
Your vehicle should use Mercon V --PERIOD
Change it at least three times, to get the Lucas out.

Have the TPS Sensor checked out.
You most likely have a Tran Pack Solenoid going bad.
It is bolted to the valve body. You can do it yourself

sounds like the symptom of a bad clutch, might need adjustment at local repair service.

Time for a transmission full service.

if your driving it normal your shift points should be from 1st to 2nd=18 to 22 mph
2nd to 3rd=28 to 32mph
3rd to od=48 to 50mph
these all change by how much throttle pressure is being use,
are you sure it's not fuel filter or plugs and wire surge your feeling

Check both O2 sensor(s) and catalytic coverter.. P0420 means catalyst below threshold. Also check the sensor at the transmission and solenoid.

you need to replace clutch pack for that gear can be ordered seperately from parts store or dealer if you want to save money call peach street auto recycling at 1800-365-2341 for a warrantied used one! also might be time for change trans filter and fluid filter could be slightly clogged but I lean towards clutch pack I replace these alot on Hondas