Check Engine light intermintent - starting issues

Thanks for anyone's time who looks at this.

92 240sx stock ka24de

Hard starting, need to press gas sometimes to start also didn't start (starter wouldn't turn over)

When at a constant speed will sometimes lose power as well as check engine light appears (will go away if I rev for an instant)


Have checked the electrical system and battery, starter, alternator seem fine. Checked grounds and no noticeable issues there.

I've been recommended to check ECU codes and have a Chilton's but couldn't find step by step instructions to do so, nor do I know if I have the correct tools.

Also been told that this could be a Throttle Position Sensor issue. If so is this just in need of adjustment or do I need to replace.

Thanks for reading this and any help is appreciated.