Am having an issues where my 300zx while die after I try to put in in reverse or drive. The car will start right up but the rpms are usually higher then normal, but goes back down once it warms up (which should be normal from what I know). Ive fixed a small fuel leak it had and checked for any vacuum leaks as well, but can't seem to find the issue. Read some where to try and disconnect the TCC solenoid and It should will only affect my fuel mileage. If someone could help tell me where the tcc solenoid is at that would great or any other solution too.
I have tried looking for similar post and searching diagrams also before anyone suggests to search the forum, but thanks for anyone that can help

You shouldn't unplug things. If you're experiencing poor mileage you should find out why.

Shutting off once in gear can be a symptom of a bad or more likely dirty aicv. it's on the back drivers side of the intake plenum. take it off and clear thoroughly wiht carb cleaner or similar.

I imagine it would be somewhere on the trans harness, check the FSM in my sig.