engine/transmission hesitation... i'm at a loss and need help. please..

[lmike0717]

I've been working on my 280zx for quite some time now, off and on whenever i can spare the money, after replacing the fuel pump,starter, fuel injectors, fuel filters, clutch and a new timing chain, the car will start and idle fairly well. however whenever i get it going it will begin to hesitate and "nosedive" once it reaches operating temp. and the rpms hit around 2.5. i'm not trying to break any land speed records i would just like it to operate as it should. i'm at a loss as to why it is doing this and would greatly appreciate any help. my cousin believes it is the synchronizer but i do not know much about the inner workings of the transmission so i have no idea... any suggestions? thank you.

[SteveJ]

You aren't providing enough detail to get any sort of diagnosis. Synchros come into play with shifting. Is the car having problems going into gear?

Is the loss of power momentary? Is the loss of power continuous until the car cools down?

What is the temperature gauge reading when the loss of power happens?

Wild speculation: Loss of power when the car gets up to temperature is frequently the sign of a failing electrical/electronic component such as the ECU, ignition module or coil. However, most of the stories I've read on here usually have the car cutting off when that happens.