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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14 Comments on "2004 Chevy Impala Engine Misfire Code P0302"
My wife car is a 2005 impala. It takes about 3,4, 5, tries to start before it actually starts.whatmay be the problem?
Pls help
Have chevy impala 2004 3.4. Misfire on number 6. Changed wires a d plugs. Check engine light will sometimes flash. Then go off then back on. What else do i check .
Check for a sticking or plugged fuel injector, lastly, check for a broken valve spring under the valve cover.
I have a 2003 Chevy Impala. Car runs fine then will just quit at times. Plugs,wires, fuel filter and crank sensor has been replaced. Still same problem.ignition module checked out good. Code says intermittent fire all cylinders and intermittent fire #2 cylinder. Cam sensor was replaced also. Still same problem. What else can problem be, or what else should I check??
You have a bad ignition control module. I know you said it checked out good, but there is no tester that can test an ignition control module properly. It is just one of those weird things in the auto repair business. It cannot be done. I don’t care what kind of machine is used, none of them are any good.
i have a 2005 impala v6 after the car starts its intake gets really cold can some one tell me why its doing it
The intake gets cold because the cold coolant is circulating through it and the cool outside air is going into it. As the engine warms up, the intake will get hotter.
I have a 2001 Chevy impala with a loud tapping noise when it’s cold but goes away when warmed up . I don’t believe it’s a lifter or rockers the noise seems to be coming from the fuel injection I ALSO get a strong smell of gas when starting. The car doesn’t seem to have lost a lot of power. Any help would be appreciated.
The strong smell of gas is from a bad fuel pressure regulator. On the 3100 or 3400 engine, these can also give a tapping5 sound, but not on the 3800 engine. If you can tell me what engine you have, I can give you a link to how to replace either one easily.
i have 2001 impala misfire 2 i have sapark fruel good injektor
If you are saying that the engine has spark, fuel pressure and a good fuel injector, then you must have an internal engine problem like bad compression or valve rockers that came loose.
I have a 2003 chevy impala 3.4 liter # 1 cylinder misfire, lack of power and a tapping/knocking noise. Replaced plugs & wires. # 1 cyliner has great spark, could a bad fuel injector cause this or is it a valve, rocker arm or rod?
Yes, the tapping noise is most likely a rocker arm that has come loose. Especially if the intake manifold gaskets have been replaced in the last few months.
my 2001 3.4liter V6 chevy impala will not accelerate properly or idle properly..Going up any hills the mphs drop drastically.It barely accelerates on flat land.I can smell gasoline fumes very strong when i start it.I can put the accelerator pedal to the floor and the car will rev up but there will be maybe a 5mph change in its speed…what could cause this!?
Answer: Two things you want to check here. First, a clogged catalytic converter gives these exact symptoms when it is bad. Second, a completely ruptured fuel pressure regulator can cause this condition, especially the smelling of gas fumes, but not usually such a dramatic loss of power. I would definitely bet on a bad catalytic converter. This is quite common on your style of vehicle. Get it changed out and you should be good to go.