2011 mazda 3 rough idle

[Paul17]

hello!

I have an issue with my Mazda 3 2L 2011 (113k) while drive on the highway then coming to a stop I have a rough idle rpms drop to 500 then jumps back up then I have smooth idle again.
I feel like it only happens after 40-45min drive
it has not faults stored did some research and found nothing any idea's?

[Johns 08 3 GT]

Give the throttle body a clean.

[Paul17]

ok I will try that thank you!

Give the throttle body a clean.

[JonsMazda]

While you're at it, clean the MAF sensors as well.

[morganc]

If MAP and TB fix it, perfect. If it's still a bit rough after, and you're feeling *really* ambitious; change the PCV valve

[JonsMazda]

Oh and don't forget to reset the ECU after.

[Paul17]

im I able to perform the ecu reset my self or does the dealer need to?

Oh and don't forget to reset the ECU after.

[Paul17]

sounds good thx!

[Paul17]

yeah the rough idle seems to always happen when im coming to a stop after 45 drive on the highway I can see the rpms drop to 500 then back up again.
I do 90% highway driving

[sarujo]

@Paul17

if you have the 2.0L MZR (non Sky) then after you have done what others already suggested, try a bottle of Redline SI-1 fuel system cleaner.

[kaleshnikov]

Do you have an OBD2 scanner? Might want to check your fuel trims and see if you have a possible vacuum leak anywhere.

Clean MAF sensor, throttle body, replace air filter (if dirty, check it using light), use some Seafoam and then see if that is fixed. If it's not, time to start looking at some diagnostic information from the ECU to spot any vacuum leaks or other sensor related issues.

[JonsMazda]

im I able to perform the ecu reset my self or does the dealer need to?

You can do it yourself. Unplug the negative battery connector for 5mins, plug back in, turn car to ON for 5 mins while waiting use all the electronic gadgets like AC full blast, turn lights on, headlights on and so forth then crank the car and go for a drive....