Car has rough idle, big loss of power, black smoke from exhaust, smokey smell of flooding

Asked by Jun 09, 2012 at 06:59 PM about the 2005 Pontiac Sunfire

Question type: Maintenance & Repair

Parked my 2005 Sunfire last night and everything was fine. Started car this morning and it is like the engine has
no power, and the idle is not smooth and responsive. It is like the car is flooding out and is getting too much
gas to burn in engine. I get a trouble code of 0300 which indicates an engine misfire. The car does not backfire
and the engine runs evenly but sort of idles weakly. When I try to drive the car it has no power and won't
accelerate hardly at all. I replaced the oxygen sensor, and installed new spark plugs. Two of the plugs were
fairly black. It seems to me like the air/fuel mixture is way to rich. I there a sensor or something that controls the
air/fuel mixture and if so is there a way that I could check to see if it is functioning properly. Thanks.

9 Answers


You are correct, black smoke means a lean mixture. The miss fire code solidifies this diagnostic. Most common cause: Clogged air filter. Check it first. If the filter is good, second step is MAF sensor and throttle position sensor. The fuel injector sensor is the next step. If after all that, it's still a problem, the fuel injection system itself could be bad. I.E bad injectors.

3 of 3 people found this helpful.

Black smoke usually indicates a rich mixture.

7 of 7 people found this helpful.

next.. check your sparkplug wires and ignition coil & module. one or two cylinders are not firing.

1 of 1 people found this helpful.

maybe yell at your gf for switching the 2 plug wires around ;) lol j/k. I'd start with checking the air filter...then make sure all your vacuum hoses are connected but, it sounds like ur exhaust converter is plugged...or maybe the ole' bananna in the tailpipe the car at night and see if the converter has a red glow..if so...converters plugged. I may joke around alot...but, I been working on cars for over 25 years

4 of 4 people found this helpful.

i changed the converter and new plugs new wiers new coil and now power and getting to much gas ,and the converter is red what wiill do next lit me know

7 of 7 people found this helpful.

maybe your injector is stuck open.. have u seen which cylinder haws the fuel on the sparkplug?

4 of 4 people found this helpful.

Now I have the same problem but could anyone help me out on this??? I got the car it runs fine the way it is now but they had to cut the wires to the forth injector and ran those injector wires to the third injector and it runs OK just a lil misfire but when I hook it up the right way it give it too much gas the car misfire I checked the voltage and it goes crazy. So I just need to know what that is. ??? ECU?? Or bad wire??

2 of 2 people found this helpful.

I have an 02 yukon xl blowing black smoke hard idle issues suckin gas down like crazy more than usual and i fixed it with an simple replacing the 02 sensors

1 of 1 people found this helpful.

Worn timing belt, rough idle, no engine code....... No power off idle.... Replace timing belt, and nylon/plastic belt adjusters.......

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