1993 mazda 626 automatic shifting problem?

[goozg]

It 's a LX 2.0 engine. When it is cold works fine and shifts normally. When the engine warms up it shifts 1st to 2nd gear normally, but hesitates 2nd to 3rd and 3rd to 4rd. After shifting the engine rpm drops from 2500 to 700-900. The car loses lots power after shifting.
I've checked engine oil and the level is fine. Any ideas?

* 4 hours ago
* - 3 days left to answer.

Additional Details

2 hours ago
It 's a LX 2.0 engine. When it is cold works fine and shifts normally. When the engine warms up it shifts 1st to 2nd gear normally, but hesitates 2nd to 3rd and 3rd to 4rd. After shifting the engine rpm drops from 2500 to 700-900. The car loses lots power after shifting.
I've checked the transmission fluid and it is fine. Any ideas?

 

[BlackPanther]

Sounds like the engine is the problem more than the gearbox.
I would get the engine coolant temp sensor checked as this can cause fueling problems when engine hot.