Hi everyone,

I just had the timing and valve adjustment done to my 1977 280z. I don't know if there's any correlation but my idle has been very inconsistent. Normally, my idle is at a consistent 1100 RPM but lately it's been all over the place. Half of the time it's at 1100 RPM but sometimes it's at 1500-2000 RPM. If I rev the engine on neutral and let off the gas, it sometimes lowers to only 2000 RPM.

There was a vacuum leak that the shop fixed when they did the timing and valve adjustment. What could this issue be?

I'd go back. Sounds like the vacuum leak wasn't fixed or you have more. 

They could have the timing right now but forgot to lower the idle adjustment which is too much airflow just like the vacuum leak.

 

This is nitpicking bulls**t but look at the front of the valve cover above the thermostat housing, driver's side. They could've put the gasket on upside down. I guess an easy way to test that would be removing the oil fill cap and see if there's a change in rpms.

If they drop you most likely won't have a vacuum leak that small...

Edited August 22, 20195 yr by siteunseen

On 8/22/2019 at 3:11 PM, siteunseen said:

I'd go back. Sounds like the vacuum leak wasn't fixed or you have more. 

They could have the timing right now but forgot to lower the idle adjustment which is too much airflow just like the vacuum leak.

 

You were right. Since they were able to fix the vacuum leaks, the Z is running better. I had to back off the idle quite a bit. It’s running much smoother now! Thank you!