Spark plugs, 3VZ-FE. lean?

[gjz30075]

Hi all,
I'm getting a check engine light code of 25, meaing overly lean. The plugs look like this:



Could the plugs in the bottom row look lean? They are pretty white. The other bank (top row) looks to have two slightly rich plugs and one normal.

Car runs great, compression is 180 all around, fuel pressure vsv valves seem to check out fine. Not sure about the O2 sensors though. The lean bank seems to have a bad sensor, per our tests but a bad sensor using will make that bank run rich, right? A bit confused here.
Any ideas?
Thanks.

[davemac2]

plugs look fine. check your intake hose carefully for any cracks. it might be your O2 sensor as well.

dave mc

[gjz30075]

Originally Posted by gjz30075

The lean bank seems to have a bad sensor, per our tests but a bad sensor using will make that bank run rich, right? A bit confused here.
Any ideas?
Thanks.

Thanks for the response dave. I'm not quite right here. The alleged bad sensor, per our tests is on the bank with the rich plug. But not really sure why the cel 25 would show up.

[toyo22r]

I had a similar problem with a 3VZE in a 95 4Runner. Replaced o2 sensor as the obvious choice but what it turned out to be was dirty injectors. I removed them and sent them out to be ultrasonically cleaned. They guy who cleaned them said their flow was not too far off, but enough that the ecm didn't like. Don't wait on repair. I went six months with check engine light on and ended up burning an exhaust valve from the lean condition!

[davemac2]

toyo22r's suggestion on the injectors makes sense to me as well. As well, check your fuel pressure to make sure it isn't marginal.

dave mc

[ASG14]

Start with the simplest thing first. Check all the vacuum hoses and EGR for ait leaks. I just had a CEL for Benk 1 lean on my 1MZ, and it was just a stupid vacuum leak.

[gjz30075]

Good info. Thanks guys!