My 1991 ls400 has started acting up recently. At full throttle the car downshifts for only a split second, than slips back into a higher gear. Under hard acceleration the transmission only kicksdown when it wants to. Under normal driving the tranmission generally shifts smooth, but has the occational hard shift. I just drained and filled that transmission fluid, and there where no metal shavings in the fluid and the fluid was not black. The magnetic drain plug had no metal shavings on it either. The engine runs fine (as well as it can with 250,000 miles on it), but I think it might be the TPS. Any input would be greatly appreciated. I have searched the forum and was unable to find a similar problem to mine.

Thanks,
Asad Chinoy

 

I'm having the same problem. Any ideas?

 

There is a Kick Down switch on the floor board under the gas peddle. I don't know much about it but it may be the cause.