Rough idling on startup, goes away after warmed up?

[optimusp517]

What could cause it. Here's a few things that's been changed recently:

-o2 sensor
-spark plugs

Is there a leak somewhere or what could cause it? Like I said whenever the car starts up it idles really rough and makes squeeky noises. Once the car has been driven for probably 10-15 min it all goes away. Also when it's sitting at the stop light it does constantly until it warms up, but when I give it gas it goes away.

Anyone run into this and what could be my possible fix?

[jlevie]

That could be caused by an intake leak.

[optimusp517]

intake leak. So the boot?

[txtorquemade]

Could be the boot, or the vacumn hoses, there are a lot of those suckers.

[norwood e30]

sounds like a vacumn to me and it goes away when the car warms up then yes check that first.

[scott_is]

I could be your temp sensor. At least its what it was on
my car and it behaved exactly like yours

Scott

[txtorquemade]

Where is the temp sensor located?

[SpecM]

I could be your temp sensor. At least its what it was on
my car and it behaved exactly like yours

Scott

this is what I thought at first too

txtorquemade: on an m20, its located on the pass. side of the thermostat housing

[txtorquemade]

Thanks Spec Ill check that out

[Liam]

Are we talking about an m20B25 or 27 or an M42?

What RPM is the cold idle?

Yes vacuum leaks (intake air leaks) can cause this among a host of other things.

[Tad]

check pelican parts,
i just picked upthose two temp sensors by the thermo housing for like 7bucks a pop.

similar problem as you is why i changed em.
i'll be checking my vac hoses tomorrow.