Slight rough idle

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May 21, 2018 | 09:36 PM

mbarb55

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Teching In

Joined: Mar 2018

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Slight rough idle

Hey guys, I have a 1999 firebird ws6 m6 with a rough idle that seems to get slightly worse after it warms up. It feels like a misfire but I'm unsure. It feels fine driving, iv also noticed that my mpg seems to have gotten worse. (I don't have any exact numbers, sorry)

Things I have done/replaced:.

Cleaned maf x2
cleaned idle air control valve x2
Replaced spark plugs
New msd wires

My mods:

K&N cold air intake
Borla cat back
(I suspect and one point this car ran Nos. I found a braided brake line going from the firewall to the hatch)

I've also questioned if potentially this car has a crappy tune but can't prove it. I've attached logs from my car driving and idling. I'm hoping that someone can read the logs and let me know if something isnt right. I have a suspicion it may be o2 sensors but I'd like to be sure if that is possible .

(Apologies if this is in the wrong place)

Thanks in advanced everyone.

Attached Files

trackLog-2018-May-21_20-01-05.csv (468.3 KB, 21 views)

Last edited by mbarb55; May 21, 2018 at 09:38 PM. Reason: Forgot something

May 23, 2018 | 01:46 AM

mbarb55

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Is anyone able to help?

May 23, 2018 | 05:21 AM

Fuhnortoner

Launching!

Joined: Apr 2017

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From: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█

Vacuum leak.

May 23, 2018 | 05:44 AM

mbarb55

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Teching In

Joined: Mar 2018

Posts: 16

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I agree it could be a vacuum leak however I checked everything I can see and haven't found anything. If the logs don't show anything useful I will have to get the pcv system checked.