1995 300ZX AT N/A @ 194K mi still running smooth should I? on 1995 Nissan 300ZX

Should I... Flush/Replace:

1. The transmission fluid?(transmission still shifts smoothly though)

2. The Antifreeze/coolant?(Still operating in normal temp)

3. The diffential fuild?

and last but not the least,should I need to get the fuel injector clean (by the professionals) but I am afraid that once they flush or clean the injector... somehow few months later the injector will die and blame myself for having the injectors cleaned. I have the car for about 2 years now. The only thing I had to replace was the alternator. Currently the car runs and idles smoothly. No slugish during take off and even on highway speed. No knocking or no hesitation. I just wanted to do a preventive maintenance. Oil change is always done every 3000 miles. I also replaced it with NGK Plugs, K&N air filter, Fuel Filter and Brake pads recently. Any suggestion will be greatly appreciated.

Asked by for the 1995 Nissan 300ZX
I change the differential oil antifreeze and gearbox oil ever 30,000 miles and the brake fluid once a year or at least every second year. The "on the car fuel injection system cleaners" do a good job. If you have no idling problems or State emission test failure a couple of bottles of techrolene in the gas tank may be no harm. Change the fuel filter as well.
Remove the air intake boot and clean the throttle body.
1 more answer
these boxes prefer synthetic oil, i would drain the auto and change the filter , the best replacement oil is redline high temp auto trans fluid, at worst it will last much longer. all the n32 z300 i owned were using this fluid , coolant was 75% distilled water 25% coolant and a bottle of redline water wetter, that dropped the temp about 15 degrees on average, i agree with ngk plugs , i usedn iridium rather than platinum, i used castrol synthetic diff oil , i had no problems over 2 cars and 5 years use.