2004 Chevy Impala Engine Misfire Code P0302

Chevrolet Impala Picture

I was getting a P0302 indicator code for # 2 spark plug. I changed the wire and it went out,however when I got up to 35 mph the check engine light would flash until I got below 35 mph. I decided to change the other wires and that’s when it started to backfire and wouldn’t allow me to accelerate pass 10mph.Did I put the wires on wrong? Should the wire be put on #2-4-6 or 2-6-4.

ProTech:
Are you sure of that code? Do you mean a P0302?

Yes it is P0302.

Ok, first tell me the make and model vehicle you have, and engine size please.

It’s a 2005 Chevy Impala 3.4L V6.

As you look at the engine, the front spark plugs are 2-4-6 going to the right. You could have a fuel injector that is bad, or a clogged catalytic converter.

Thanks, I tried that and still getting the same results (it continues to back fire and stall out if I try to go past 10mph).I’m not getting the check engine light coming on.

I would really look into the converter problem, that is what it sounds like to me. Does it seem sluggish as you accelerate?

As I accelerate it just has a loud back fire.If there was a problem the converter wouldn’t the check engine light come on?

It may or may not, if it has an efficiency problem it will set a light, if it is clogged it will backfire.

If clogged how to I fix it? I don’t think it will make it to the car mechanic repair shop.

You would have to replace the catalytic converter if it is clogged. A shop should be able to tell if that’s the problem or not before doing repairs.

Thanks for your help. I appreciate it.


2004 Chevy Impala Failed Smog Test

I have a 2004 Chey Impala.Its a 3.4 V6..I went to have it smog tested and my car failed because it has a misfire in the number 2 cylinder.I was told it maybe the fuel injector. I have changed the plugs the coil packs and all 6 wire. If its not the fuel injector what would b the next step before I can consider the cat converter? Im not going to consider the computer til the end..help this lost female..clueless.

Since you’ve seemed to have changed all of the ignition components, and if they are working properly, that really only leaves a fuel injector problem. There can be particular cylinder issues such as low compression, burned valves, etc…but I doubt that is your problem. A catalytic converter would NOT be the cause of a single cylinder misfire, so I would not spend time or money in that area. You might want to recheck the ignition components, especially on cylinder number 2 where the misfire is just to make sure it’s all ok. You could have possibly closed the gap on the spark plug by accident, or cracked it during installation. If that all checks ok, then you may want to try a new fuel injector.


Engine Light Code P0113

What would be the cause of a P0113 code?

Can you tell me what kind of car you have? year, make, model, engine?

2004 Chevy Impala 3.8l

The code you have (P0113) is for the Intake Air Temperature sensor. Usually the main cause for this code is a wire breaking or becoming partially broken at the connector to the sensor.

Thank you, How would a bad iat sensor, or broken wire effect engine performance, or fuel economy?

Well if the engine computer can’t tell exactly the temperature of the air that is being taken into the engine, it can affect fuel delivery which can have a negative impact on driveability and fuel economy. It’s a fairly easy check and repair, so I wouldn’t drive it long if you don’t have to.

Thanks again, and have a good night.


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