Hello,

Changed my plugs today. They appear to be the original NGK (passenger side) and Denso (drivers side) plugs and I just changed them at 70,000 miles on my 2003 SR5 V6.

I was having an issue where the engine seemed to stutter but never stall at idle on occasion. No codes and it really has been running well the past few months I have owned it.

Side note: I did just recently get an oil analysis back and there's no coolant in the oil. So, I was thinking I may be lucky so far in terms of no head gasket leak. Blackstone report was actually pretty good. No oil loss over 5K miles. No coolant loss.

What do you guys think of these pictures?

Thanks

Bill

Those suckers needed changed. Did the idle smooth out? I would clean the MAF and throttle body as well.


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i think you should sell me that 4runner!

The throttle body was pretty dirty but honestly I can't tell that cleaning it made a difference. I am still getting RPMs well over 1,000 when starting it up. I can shift to D and back to park to get it into the 800s.

When making room to get the plugs out, I did notice a hose (ventilation hose #1?) is split on the end and the clamps are very loose. I can't find anything about it in the shop manual but assume it has to do with the PCV system. So, I will go get this today.

I'm going to be a sad person when the time comes. I hate putting miles on it. It's only a 2WD though so hopefully I can keep it going for regular driving. I'll never find one like this again. Was under $10K from a Toyota dealership but those were fall 2020 prices. So far the biggest expense was the transmission pan leaking but the fluid was good and I got that tested with Blackstone too.

I am just surprised to find the NGK and Denso combo after this amount of time. It's nearly 20 years old at this point.

I would replace that hose first and any vacuum hoses that have cracks. If that doesn't do it, then I would pull the IAC (Idle Air Control) valve and clean it. You can replace it but I would clean it first - may well solve the problem. Would replace with Toyota part if necessary. It does sound like an IAC issue to me.

Thank you. I did not know to check the IAC.

On 4th Gens 4Runners isn't the Idle Air Control valve integrated into the throttle body and not removable/replaceable as it was in earlier models?

Great question. I can't find any idle control valve in the parts database. I did find an "air control valve".

1986-2009 Toyota Control Valve 17630-16040 | McGeorge Toyota Parts

I think I will just need to get under the hood to look for something connected to the throttle body because the picture in my link doesn't show that.

Idle air control AND throttle position sensor are RIVETED to the throttle body on the 4.0. only solution would be replace the throttle body, though I would only go that route if due diligence didn't pay off with the vacuum lines, you'd be amazed what a vacuum leak can do to a modern engine

I was talking from experience with my former 3rd gen V6 and didn't know the design changed on the 4th gen so I learned something. Thanks for the correction....does it operate the same way as the 3rd gen, just not replaceable? Can it be cleaned?

Thats true and I would use an OBD reader to look at fuel trims to see if they are high . . . another indication of a leak.