Changed the plugs in my 06 awd gs300 now seems to have a slight miss or rough idle any help would be appreciated.

 

Which plugs did you change to - NGK or OEM (Denso?) Iridium?
Did you torque them down correctly?
If you're misfiring, then there'd be a code logged as such - check to see if that's the case.

 

Is there a code?

 

Check any vaccum hoses that might have been left off during the install, otherwise check for a code and diagnose from there

 

Used the denso iridium fk20hbr11. And no there are no codes it just don't feel as smooth as it did before. All vacuum hoses we reinstalled also.

 

maybe a gap on one of the plugs got messed up

 

Same thing happen to me. check the vacuum hose on the top left side of the engine. It come off easily without knowing it.

 

Ok will check the lines. It not real bad it's just enough to notice its not as smooth. I thought you was not supposed to try and gap these plugs at all?

 

You shouldn't have to, they come from the factory pre gapped.

 

yes they do, but sometimes the gap gets messed up. something falls on the carton, etc

 

this is true, but you should check them. Nevertheless, I've never had one out of gap.

 

If a hose was disconnected, the car would stumble like crazy but it's worth checking if any hoses are a little loose or damaged. If the car is actually misfiring there will eventually be a trouble code stored, but if it only stumbles once in a while then you'll only get pending codes which won't light the dummy light and you'll need to check with a reader while the engine is still running... just plug it in after going for a drive while you're parked before shutting it off and see if anything is there.

 

Over the last few weeks, I've done some major services to my GS, I did:

New Brakes
New Pads
New Rotors
Replaced Timing Belt
New Water Pump
New pulley's
New thermostat
Drained all the coolant twice, checked for any debris, topped off, burped the system, etc.
Today is new spark plug day. Got a set of Bosch Dbl Iridium, "Do not Gap" factory set at .042
Now that I'm getting ready to put the last couple of plugs back in on the driver side, I notice this little vacuum hose with a green cap on it:



I am not seeing what it plugs into.

Can someone tell me what that goes into?

 

How about that fitting thats right next to it?

 

Better lighting would have helped. That looked like it was blocked off, pulled the car out in the light, and it's a natural fit. Thanks
Pics of the plugs that came out soon.