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1.4 Cruze rough idle & random miss fire? Help!

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I have a 2015 Cruze 1.4 14x,xxx miles, rough idle, miss fires randomly, using more gas.
Anything I’ve done seems to bandaid the problem for a few days if that.
At first i noticed rpm’s were getting higher, having a rough time shifting,
engine light came on with the following codes;

changed upstream oxygen sensor & all four spark plugs.

ran better for a few days then started missing but the engine light would flash, service stabilz and traction control came up all at the same time and would go away.

engine light never stays on after flashing, if it does it’s very brief triggering code

pulled the ignition coil pack and replaced it.

ran better for a few days then back too poop.

i noticed my Cruze was using more gas than normal.
when I’d shut the car off not always but usually a fan would run under the hood. Normally I turn the car on & off to get the fan to kick off.

engine light would still randomly flash while misfiring.

sometimes oil? Burning smell.

randomly driving home one night my Cruze went into limp? Mode I think.
Barley went 5–10mph idling rough, and running hard like it was stuck in gear. All of the gauges on the dash stopped working, service stability & traction was on w/ traction light on and this time service steering came on for the first & only time with the dash light. Speedometer wouldn’t work, rpm didn’t work, only thing that worked was the gas gage.
i pulled over and sprayed starting fluid looking for a vacuum leak but got no reaction from spraying starting fluid.

Made it home and the next morning my Cruze was ‘normal’ like the night before didn’t happen?

decided to change the spark plugs again for a 2nd time.
**I noticed oil? Around the walls where the spark plugs go, the cylinder?
**noticed a white dust, corrosion light on the walls aswell.

changing The plugs a second time didn’t phase the Cruze.

still randomly missing w/ engine light flashing.
Car feels hotter getting out after driving,
Burnt oilish smell?
Pulled the coil off and there was more oil around the cylinder/ hole where spark plugs go. More white dust inside the hole and gradually building up on of the engine.
White residue in ignition coil boots.

had a blocktester put in coolant tank and fluid stayed blue.

Had a small leak on coolant tank & replaced tank
Got a doorman valve cover w/ the gasket and replaced the original.
more oil and white residue building up.
rough idle, seeming like the cars having trouble shifting. Losing acceleration esp up hills or on the interstate.
The rpm’s did go down after letting the Cruze idle after the new valve cover n gasket, but still runs higher accelerating or just coasting down a steep hill the rpm’s are high

lastly I just replaced the throttle body, and the gasket.

rpms still kinda high,
A possible new whistle noise?

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· Registered
2015 Cruze 1.4L engine 6 speed AT
1,229 Posts
You have all the symptoms of a corroded ECM connector. First thing, I would inspect and clean all three wiring harness connectors going to the ECM. Get some electrical cleaner, disconnect, inspect and clean each one.

Second, you replaced the O2 sensor. What part number, and vendor did you use.

Third, you probably new a new valve cover.
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