Hello CL,

I recently just purchased a 2010 IS250 and everything seemed fine until I took it on the highway heading home after buying the vehicle. While driving, if you downshift from 5th into 4th and you're on the throttle the car will hesitate to go into 4th causing the car to jump up to redline because you're on the throttle and won't go into gear until you let off the throttle. You do the same procedure, but not on the throttle and simply downshift. She'll go into gear just fine. I don't understand what's wrong because no lights have come on or codes. Is it a throttle position sensor issue? Torque Converter solenoid going bad? Needs a transmission fluid change? Any advice would help

PS. It only happens from 5th to 4th. No other gear changes.

Thanks!