I have an 06 350z. I recently replaced spark plugs, could cleaned tb and mass air flow sensor.. And it still has a rough idle and care shakes. And suggestions what it could be

 

check your coil packs. Start the car and start un plugging them 1 at a time. If the idle drops, you know that one is good. plug it back it and move onto the next. if the idle doesn't change when you unplug the coil pack, then you know you have a misifire. it's probably time for new valve covers.

 

I'm going to try that. Hopefully is just a cool and no bigger issue. As changing the valve covers would it be suggested to replace both valve covers?

 

Do you have any codes or pending codes? Have you scanned the ECM yet? A rough idle can be caused by a number of things. Coil packs are certainly part of the list, but you could also have issues with a fuel injector(s), bad gas, weak fuel pump, MAF sensor, cam sensor, O2 sensor(s), vacuum leak, etc.

Before throwing more cash at the issue, get the car scanned. Also more history on the car would be helpful. Things like mods, mileage, etc.
-Icer

 

That's where my money is at. Since these cars are notorious for having oil leak through the spark plug tube seals and into the plug/inside the coil pack.

If changing one, I would change both. It's not a fun process.