Transmission slips when engine is cold, shift better when engine is hot.

Hi all,
My 99 Camry has over 160K on it. Recently I notice the following problem: If I don't warm up the car (engine cold) transmission will slip between gears, sometimes it won't even shift. The longer the drive, the better it shifts. However, the slipping never actually goes away. Even during a long drive, when you stop and go, if you push rather hard on the gas pedal, the idle will go really high, to >5K before the gear shifts.
I did a transmission fluid exchange about a month ago. After I did it the transmission shifted fine, no more slipping; but then the same problem came back about a week ago.
Does anybody know what the problem is? Please give me some suggestions.
I'd really appreciate it.

Interesting. I had that happen to me a few times, but only in extreme cold. When it got around -10 degrees and my car was sitting outside for 9 or 10 hours that happened to me. But it didn't slip after 2nd gear. Only from neutral to 1st. It's only done that 3 times in 3 years in extreme conditions. I'd be curious too.

Pete,
Changing the trans fluid wasn't the cure although I would have also suggested this as the first step in the process. At this point, the best thing to do is to have it thoroughly inspected at a trans shop or at the Toyota dealer. Maybe the fix will be cheaper than you think; who know till you get it inspected? Best of luck. :2cents:

Pete,
Changing the trans fluid wasn't the cure although I would have also suggested this as the first step in the process. At this point, the best thing to do is to have it thoroughly inspected at a trans shop or at the Toyota dealer. Maybe the fix will be cheaper than you think; who know till you get it inspected? Best of luck. :2cents:

Thanks Bossman for your reply.
This morning I went to AutoZone for "check engine" check. Here is what the computer says:
- Oxygen Sensor
- Sensor - Vehicle Speed
- EGR valve

And last but not least: SHIFT SOLENOID. The guy said it is the cause of transmission slipping. And the dealer is the only place that sells it.
Plus I just found out that the transmission fluid is leaking, alot.
So, I guess my questions are: are leaking fluid and shift solenoid related to each other? And how much it will cost to replace the shift solenoid?

About those sensors, if I can only afford to fix them one at a time, which one would have to be done first?

I know I asked many questions, but I know I can count on auto experts in this forum. I really appreciate your advice.
Thanks, Peter.