A few days ago I replaced my spark plugs on my 2003 Maxima V6 and had to remove the intake manifold.

Now I'm experiencing a very low idle (around 300rpm) and I have to push the gas pedal while starting the engine or it will just start and stop 2 seconds later (the rpm drops to 0 unless I push the gas pedal for about 5 seconds while starting).

The service engine light is on and code reading reveals P0506 NISSAN - Idle Speed Control System RPM Lower Than Expected.

What should be my next step? I'm pretty sure I reconnected the intake manifold hoses correctly and everything is where it should be. Should I just start by cleaning my throttle body?

Thanks.

 

Did you replace the intake manifold gasket with a new one after putting everything back? If you didn't, the seal might not be good.

 

I did not replace the gasket, it didn't look warped at all. But maybe it shifted a bit when I put the manifold back on top? The gasket was laying on there pretty loosely (no sealant or anything).

 

It most likely is the gasket leaking. Get a new gasket. Re-using old gaskets is not a wise thing. You don't need to put a sealant on, the original didn't have it. Using it is a type of insurance.

 

It does seem like you have a vac leak. Spray some carb cleaner around the gasket and see if idle changes. If it does, it's time for a new gasket.