2010 Mazda3 Sport, rough idle in the mornings only

[KodaDog1024]

Hey folks-

First post here, so please forgive me if this was already posted, but I did a quick search and didn't find anything. So I just bought a used 2010 Mazda3, 2.5 liter with 52k miles on it. I've been noticing lately that my morning start-ups are getting slightly worse here and there and by that, I mean the idle is quite rough (and has even stalled once after it rained). And if I don't drive the car on the weekend, Monday mornings are quite rough as well. But after 20 seconds, it smooths out and then is fine for the rest of the day/drive time. Any ideas before I take it in for diagnostics? Is this normal? Thanks in-advance for the help.

 

[DarkRyder]

Almost sounds like the IAC needs to be cleaned. Is the check engine/cel light on?

 

[concept]

Have you gone through a couple of tankfulls of gas since you started noticing the rough idle? I would throw in a can of Techron, the next time the tank is filled, and run through most of that mixture to see if things improve.

 

[KodaDog1024]

Almost sounds like the IAC needs to be cleaned. Is the check engine/cel light on?

Thanks for all the reply's. I do not have any check engine lights on, neither during start up, during or after it happens.

 

[KodaDog1024]

Have you gone through a couple of tankfulls of gas since you started noticing the rough idle? I would throw in a can of Techron, the next time the tank is filled, and run through most of that mixture to see if things improve.

This will actually be my second refill since I got the car (about a month ago). I don't drive the car very much (to work and back is like 2 miles).

 

[DarkRyder]

If it sat for a bit running cleaner through it will do it some good then.

 

[KodaDog1024]

Ok, update. I ran a bottle of Techron through, almost finished with that tank. My car sat over the weekend and this morning it had a hard time starting up, even stalled once, then after about 10 seconds (while lightly giving it some gas at start up) it even out and then was totally fine. Now when I go out to start it up, more than likely it'll be fine at start up as well. It's when it sits for more than a day that it putters at start up and then evens itself out. Thoughts?

 

[concept]

I haven't looked at my MAF sensor in my 3, but typically this sensor has a heated wire that allows it to determine airflow by how much temperature drop occurs (across the sensor wire) at any time.
Now if the previous owner over- oiled a K&N air filter, some of that oil may coat the MAF wire and cause idle issues. If this is the culprit, gently cleaning the wire with CRC MAF cleaner could resolve the issue.

 

[KodaDog1024]

I called a very reliable shop and he said since it was "temp" related, more than likely without looking at it, he guessed it was the Air Charge Sensor or the Coolant Sensor. I don't know.

 

[concept]

Quite possible and would require checking each - a good place to start.

 

[danianzueto]

You need to change your Purge Valve, this is the cause.

 

[KodaDog1024]

is this hard? Can I just remove the PV alone?