MR805ER

just replaced plugs in my 2006 GS300 and after firing up it felt like it was misfiring and shaking for about 20 seconds then it normalized and ran good. in the morning when turning on it did the same thing for 10 seconds then fixed itself again.Before I changed plugs it wasn't doing this at all. any ideas

MX73

What kind of plug did you use? Did you make sure the gap is correct? All connection good?

MR805ER

The connections are good and the gap was set. The plugs I used are NGK Iridium IX

MX73

Are all the vacuum lines connected and in good condition?

MR805ER

Did a visual and they appear to be all good.

MX73

Is it throwing any codes? Maybe disconnect the battery for a few mins and reconnect.

MR805ER

No codes-I’ll try the battery in the morning-I also failed to mention that the NGK plugs I put in are about 1/4 inch shorter on the thread side then the ones I pulled out but I checked and the NGK’s were definitely specked for use with this car which I thought was kinda weird- I’m already planning on switching them out.

MX73

Do you still have your old plug? You could throw them back in there and see if it misfires.

NGK part number 6858, DFH6B11A, gap .044mm

MR805ER

Yea I might do that to thank you

2013FSport

iTrader: (2)

He could have a defective plug. Good test!
PS minor correction up there...
0.044" / 1.1mm

aristo1987

There was a thread about this years ago and it was confirmed that we cannot use any aftermarket spark plugs on our vehicle. Lots of ppl had nothing but problems like misfiring, engine over heating and shakes.

You will have to buy oem denso toyota spark plugs

MR805ER

Went and bought new Autolite plugs that were the longer length ones last night and put them in this morning-fired it up and no misfiring-I will definitely consider changing the autolite plugs with OEM denso ones just to keep everything original. Still with new plugs it works good-thanks for all the info everyone-new to this forum and I love it

2013FSport

iTrader: (2)

Hindsite says plug reach on DI engine is critical for combustion. Unlike a a port injection engine where air fuel mixture has a port, a valve, and added turbulence to mix the AFR atomizing the fuel into the air, a DI engine when started cold there is far less atomization of fuel into air. The plug being recessed if firing and lighting a pocket of air void of fuel.
Add that extra 0.30in of extension and the plug is in the combustion chamber lighting the fuel.

It begins running better as the engine warms because the heat helps atomize the fuel vapor, hence it appears to smooth out.
The 2GR-FSE has over a 1.0in reach... Im not sure about this one but guess it is near the same.

OP - can you post a side by side pic of the NGK and original plug comparing the plug reach from the washer to the tip as well as the plug #?

MR805ER

That’s some great info and I’ll will post a picture of the plugs when I get home from work tonight

MR805ER

The ones on the left were taking out and replaced with the ones in the middle which were the ones causing the misfiring so I replaced those with the ones on the right which are the same length as the ones on the left and misfiring went away