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Discussion Starter #1
this car is actually my girlfriend's. she absolutely hates it. i've never seen a 5 year old car with so many problems. i think the cylinder all the way to the passenger side ( im not sure which number cylinder that is) is dead. i replaced the spark plugs, and i noticed that the old plug in that particular cylinder came out completely black on the end. i was thinking maybe it was unburned fuel. anyway, has anyone had this problem? thanx a lot for your help
 

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Not sure what you mean by "dead"

First describe the problem in detail. Is the car low on power, is the check engine light on, is the exhaust unusually white or blue? Does it cough or miss?

Once the problem is identified then there are some quick diagnostic tools...is there oil floating in the coolant? Is the oil on the dipstick foamy? Check the spark, especially on that #1 cylinder. quickest way is by putting a timing light on that wire, but that won't tell you how strong the spark is, just whether its there or not. There are other quick ways to check spark as well, but you must be careful and know how to do it right.

Mark in MA
 

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2015 Buick Verano "Leather Group", 2015 Kia Optima Hybrid
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Black plug usually doesnt mean a thing...
thing to look for is there any black residue on the wires. Like that you can rub off??
if so you might have a bad seal on the plug resulting in blowby.
maybe when you changed the plugs or the person before you did it they might have left the gasket down where the plugs sit?

but a black plug is not anything to worry about.
if a cylinder was gone the car would have no power and a blinking check engine light...
 

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Discussion Starter #4
the check engine light comes on and then blinks and then stays on solidly. it goes back and forth, but its never off. the car has a horrible loss in power. not a miss. its a loss of power, and its constant. thats what i mean by a dead cylinder.
 

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Loss of power.

Timing belt off by a tooth? Put crank at #1TDC, pop off top half of timing belt housing and check for intake and exhaust cam gear marks lining up correctly (I'm assuming the engine is 1.8L DOHC)

Compression low? Check the compression with a compression tester on all 4 cylinders.

Weak spark? Check for a good blue spark jumping to ground.

If a cylinder's not firing, then the typical diagnostic tool is to pull the spark wires out one at a time with the engine running, and determine which one does NOT have a commensurate drop in RPM when it is pulled. This is a bit difficult with the coils on top mounted the two of the spark plugs directly, but you could at least check the other two cylinder for this condition.

But first and foremost, check the trouble codes and see what the car thinks is wrong.

Mark in MA
 
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