Yesterday 02 impala with 3.4 starts misfiring pull codes get a "cylinder 3 misfire". Go to dealer tell them to change the plugs. and they start going on about diagnosis charges and such and say they doubt it's the spark plug, but the car has 103K miles on it. Any suggestions?? tryin not to spend too much money on it because im tradin it. Any help would be great.

It probably would be cheaper in the long run to let them do the diag on it. I don't know how many people have came in saying they need plugs or the such and then when that doesn't fix it they are mad at the tech for not correcting the problem. Could be plugs but could be wires, coil, injector, wiring or even something like a base engine misfire. I would recommend letting a proper diagnosis be done. but yea with 100k miles if you have never R&R plugs it definetely wouldn't hurt but you still may have a misfire.

With 100k plus on the engine, if you have never changed the plugs a new set with some wires sure wouldnt hurt anything. These engines are known for injectors going bad. Thats where Id put my money. But... plugs and wires are a gamble. They need to be done any way and just MIGHT fix your problem.

Just curious, but how hard are plugs/wires to replace on these cars? Been thinking about buying one for the wife, but I like to do alot of that kind of routine maintenace and don't want something that is a pain in the butt. She had an 89 thunderbird before it spontaneously combusted and I looked at the plugs (or tried to) and said no way I'm gettin in that.

Changing the plugs on these is hard you have to tilt the engine forward to get to the back plugs.

Changing the plugs on these is hard you have to tilt the engine forward to get to the back plugs.

I disagree with the statement above. Changing the plugs on the 3400 or the 3.8 ltr. is not required nor are they designed to be tilted forward. The most difficult part is removing the rear plug wires without damaging them (clips are tight on plugs and plug wire puller may be best bet). Access to the rear plugs is helped by removing the support brace at the rear of engine compartment and not all that hard a job.

Thanks, I'll have to look at my brother in laws impala

Yesterday 02 impala with 3.4 starts misfiring pull codes get a "cylinder 3 misfire". Go to dealer tell them to change the plugs. and they start going on about diagnosis charges and such and say they doubt it's the spark plug, but the car has 103K miles on it. Any suggestions?? tryin not to spend too much money on it because im tradin it. Any help would be great.


i had the same thing happend..and was told it was the EGR VALVE..

nor are they designed to be tilted forward. That is totally wrong, the engines CAN be tilted forward. In fact I even bought a special tool called an engine tilter, that will allow you to tilt the engine forward.
Here is one such tool
http://www.toolsource.com/ost/product.asp?sourceid=googleautotools&dept%5Fid=500&pf%5Fid=91581&mscssid=W0C1J8D25R8W9GP968WF5NTB5JPQ3GUC
It makes life so much easier to change the back plugs and work on the EGR , MAP , OX sensor , coils , plug wires ...etc...etc GM knows what they are doing
You can do it with out the tool, but i hear the engine flops forward and before you misinterpret the AD , FWD means front wheel drive.

I have that same tool, and you'd have to pry it from my cold dead fingers to get it away from me. The Impalas have enough room under the hood to change the rear plugs without using it ( I did my 99 Grand Prix GT without using it) but other GM models like the older 88-96 W-bodies are impossible to do without rocking the engine forward.

Last poster is right. I change mine 3 times without special stuff. But i am not sure this is plugs. I am not saying this is not plugs i just trying to tell, I change a lot of stuff and still having a problem. You can take a look on posts pages before as "NO CAT", "Help P0420" etc. They all in one disscushion. But my story coming soon, i gonna tell you what i had. Even the dealer cant find the problem. So this iam using method illumination (spend around 3000$).

i had the same thing happend..and was told it was the EGR VALVE..

I was told the same thing as well