My car is honda accord 1992 AT. When the engine is hot, the auto transmission is slowly to change from gear 3rd to gear 4th, maybe 2600-2700 rpm to change (normally about 1800-2000), although everything is normally when engine is cold. What troubles is happened with my car? Help me, please!!!

 

Can I ask when the trans fluid was last changed?

Can you verify that there are not any stored codes in the ECU/TCU?

 

besides the fluid which is the first place to start,have you checked your accelerator cable to makes sure it hasn't stretched over time or is out of adjustment? if it is,it can affect the transmission cable and cause erratic/hunting shifting issues.

 

- The trans fluid has been changed about 600-700 miles ago
- There is no code alarm in ECU or TCU
As I said, everything are ok when the engine is cold. I wonder why? hic hic....

 

Thanks for your advice, I checked as you told but the cable is ok. I have been thinking about the solenoids, they may have been weakened, so when they heat up, they work slowly, right? Do you think as me?

 

Back probe the TPS for correct voltage changes.
Verify that the transmission control cable between throttle body and transmission are correctly adjusted.

 

I just measured the voltage of TPS at garanty, it's 0.49 V, is it ok?
The cable between throttle body and trans are correctly adjusted.

 

You will have to check the TPS through its sweep. If the carbon tracking has a bad spot the ECU/TCU will not command an upshift. From closed throttle to WOT you will want to make sure there is a constant linear change. If there is a loss of voltage then there is a dead spot on the track and the TPS will need to be replaced.