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Hello!
I apologize if this is long, been dealing with this for a long time lol.
I have an ongoing idle issue I need assistance with, I should probably say that idle issues seem to be a problem with these cars, but so far all the tips I’ve tried have failed 🙁 my dad was a GM mechanic so I learned a lot growing up but I am completely stumped here. Unfortunately I do not have a live data tool.
2012 cruze, 1.4l turbo engine. Automatic transmission. 86k miles is that helps 🙂 I do not have a check engine light, never gave one either 🙁
It has an issue where it idles rough when cold, then when the engine is warm it has a dropping idle. It will idle fine around 700 RPM then randomly drop to 500 and it gets rough, then catches itself and idles fine. It’s interesting to note that it’s like that if the AC is on or off, it thought it was the compressor at first. Zero change. It also doesn’t have a problem starting at all.
Things I’ve done:
New spark plugs and spark plug boots
Vaccuum leak test
New o2 sensors
Cleaned MAF
A common problem with these cars are missing check valves, I noticed one of mine was missing and unfortunately it is non serviceable so I bought a brand new intake manifold. It came with new MAP sensors,
Fuel rail and fuel injectors, throttle body, check valves, gaskets, purge valve, IAC and brake booster. (Yup it cost $600)Another common issue was a failing pcv burst disk in the valve cover so I bought a brand new valve cover. (Yup, $180 for that sucker) I bought it because the car had the infamous burning oil smell and this fixed it.
I refuse to believe this is normal for this car. It’s idling rough and then dropping like it wants to stall. I don’t know what else to do…
The car has 2 temperature sensors but I feel like if those were an issue it would have an engine light? It has a coolant temp screen and it hasn’t given an indication that there’s a problem.
Thank you in advance!
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[quote=”Fightingmarmot” post=186171]
The car has 2 temperature sensors but I feel like if those were an issue it would have an engine light? It has a coolant temp screen and it hasn’t given an indication that there’s a problem.
[/quote]Inaccurate ECT readings within range will not usually throw a CEL. I would pull the sensors, clean them thoroughly, reinstall and test. If that doesn’t make a difference, I would ohm them out at room temperature and in boiling water.
Hello!
Sorry about the delay in response.
Turns out it was the spark plugs. The ones the car uses are iridium and I was told not to gap them because it could damage the electrode. Well I went onto a cruze forum and people were saying how they had the same issue and found out the pregapped iridium plugs were way off out of the box. They switched to a copper plug and it seemed to do the trick.
I thought what the heck for 10 bucks I’ll try it. Gapped them to the .028 and the car is like a rock now. The manual I think wants it under .034 and the iridium ones were from .035 to .04. Had em less than 2k miles. Oh well. And they’re not cheap either.
Thanks again!
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