Low idle on cold days

[cptnsolo77]

As the subject states. We have gotten a cold spell here & I noticed the idle drops down to about 600 RPM & idles ROUGH. Its doesnt last too long when im at a stoplight. Sometimes I put the AC on to bump the idle up, then turn it off & it sometimes returns to normal. During warmer days no problems at all. It stays pretty warm here in FL so im sure the warm wheather masks the problem. I narrowed it down to the intake manifold gasket & I already priced it at the local Toyota dealer ( 6 bucks ). The MAF, PCV valve & throttle body is clean at 148K. Going to do it this weekend if all goes well.....however I dont get a CEL when the idle drops. I thought if a intake gasket was leaking it wouldnt it cause a lean condition & throw a CEL ? Just curious.

[Rayven01]

My guess is there's a threshold before the code is thrown and you haven't quite hit it yet. I've seen other people mention 500 RPM when their CEL lit up. It probably helps that the Florida definition of "cold" is a lot different than for most of the rest of us. Definitely sounds like the gasket problem though.

[JohnO]

Could be the idle speed control valve is sticking and not letting the idle adjust properly. I'm planning to clean mine soon.

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[cptnsolo77]

Thx guys, looks like i got my CEL today. P0171 , bank 1 system too lean. I think its time to replace that gasket now