92 Windom Throttle problem

hey guys

i have a problem with my 3VZ-FE windom.

starts fine, runs fine, not a problem at all... till u put the throttle down too far while driving down the road then it does the same thing any car would do when it hits fuel cut. makes no difference what gear the trans is in, or whether in pwr/eco/man, or what speed im doing

im having problems trying the process of elimination thing, even though i do have an entire parts engine (blown bearings) to use


Any ideas what this could be?


and just as a side note, can someone tell me what the little button on the top of the steering wheel cowling is, the one that tucks under the guage cluster. it only has japenese writing on the sticker beside it and its bugging me what it does lol

Check for vacuum leaks, and plugs+distributor rotor+cap. Check ignition timing.
No idea what that button does. Can you get a picture of it?