My 1990 300zx NA has been having some problems lately. I just had my fuel injectors changed out at Z1 Motorsports and these problems came up a week after i had them changed. I tried starting it one day and it cranked, but the engine wouldn't turn over. This happened a few other times too. The car now idles at about 650 rpms, compared to about 1000 rpms before. And also sometimes when i push the gas, the rpms will drop and then shoot back up. What could be causing these problems?

 

I been having the same thing. Start it up and it sits about 1000-900 than drops down to 600-400. It starts to get rough and can see it drop to 300 and feels like it will stall out and will kick back up. Mine stalled one time but no idea what it could be.

 

On top of the thermostat housing their is 2 censers one sends the temp to the computer, and the other gauge gets sent to the temp gauge in the car you wanna unplug the one that goes to the computer see if it runs better without it then you should replace that. It takes 2 sec to check and if its that it cost like $3

 

i had the same problem with mine but it was after i installed my intakes no matter what i would do it kept takign to much air was causing my car to die