Hey

I just thought I would toss this out there to see if anyone had anything to help.  My '05 Cavy just started acting up.  I getting a p0300 (cylinder misfire) error.  The car ran fine on my 3 mile errand and the next time I drove her she sputtered and hesitated bad at low rpms, but only whilst accelerating, she idles fine.  She just has very little power under 3k rpm.  I have read around a bit and some people say plugs, wires, coil packs, blah blah.  I have tried replacing the ignition mod and it lessened the severity but didnt solve the issue.  Anyone else have a similar problem or perhaps an idea where I might find a pdf manual for my car?

Anything is much appreciated guys.  thanks.   

You have the 2.2L or 2.4? I have the manual for my Pontiac Sunfire if you didn't know same thing. I can scan the pages you need and send them. Otherwise I bought mine at Pepboys for less than $20.
First think I buy with any vehicle. Get the car then get the Chilton's worth the money, time, and effort.
Mary

Coughing and spluttering are signs of something wrong with either getting too much or too little air or fuel, and or lack of a good spark to the cylinder. Here's the check-list I've used and had good results with. It comes from trial and error, many trips to the mechanic, and a lot of wasted time and money. So here 'goes...

When was the last time your replaced your air filter? Dumb question i know, but sometimes we just forget (I know i have...). Consider swapping in a K&N while your under there, they pay for themselves in a matter of months.
Have you switched gas stations recently? For myself, my truck refuses to run Shell gasoline of any type. I don't know what it is, but whatever they do to their gas just plain sucks.
Check your spark plug wires, you may have some corrosion or even a partially melted wire. Replace as needed (SP wires are cheap, so it couldn't hurt to do it anyway).
Pull your spark plugs and inspect them.


Check the gaps on them and make sure they are in spec. Also, check the heat rating on your spark plugs; you may need to go up or down a heat rating. (SP's are also cheap...)
Check your fuel filter too, it may have some gunkies in it. The higher the rpm, the more fuel needed, so if it's only happening above 3000 rpm... a filter inspection/replacement may be in order. The last time I replaced my fuel filter, it cost a whopping $3.99.
Once again, it can't hurt...
If it's still not running well, pour a can of fuel injector cleaner in the gas tank.
Pull the air intake hose off the throttle body.
Here's a pic of what it looks like with the air intake fully removed:

Grab 2 cans of spray throttle body cleaner and a buddy.You can get the pour stuff, but if there's a backfire, do you want your hand above the throttle body? Make sure the car is in park/neutral, put the parking break on (pull that lever as high as you can!) and put bricks/blocks in front of all 4 tires. Position yourself as far to the passenger side as you can (one can never be to careful) and get ready to spray. Have your friend raise the rpms to around 2500-3000 and start spraying. The rpm's will drop, so vary the amount you spray so you don't stall out. Keep going until the first can is empty.
Re-attach your air intake and make sure all loose bolts/screws/tools/etc are secured and accounted for. Remove the bricks/blocks.
Go for a 20-30 min drive on a nearby highway or main road. Vary your rpm's a lot. Don't redline it.... but definitely get those rpm's up there. If you start looking like a poorly tuned diesel, spewing black  smoke everywhere, that's a good sign. Wave goodbye to all those nasty carbon deposits!
If when you get home, you are still spewing black smoke, repeat the above procedure with the second can and go for another slightly longer drive, 30-45 min.

If after you return home, things still aren't working right, check your O2 sensor.
http://www.ehow.com/how_5193043_test-sensor.html

Good luck and I hope this helps!

Well, I didn't read the replies, but Ill give it a shot...

Your getting a misfire code, could be a number of things but you can narrow it down pretty easily.

1st, pull out all of your plugs, remembering where each one came from and look for one that is drastically different looking, if your just having 1 cylinder misfire than that plug will look different, probably fouled, black and grimey. 1 should look different regardless.

Once you identify which plug is not firing then you can start going up stream from there, look at the boot of the plug wire, look at the wire itself, make sure it's still pliable, not dry rotted or cracked and possibly arching out on a metal engine piece. For diagnostic purposes you could swap a wire with a cylinder that you know is firing, clean a spark plug, install it back in the misfiring hole and go for a decent length ride, pull the plug and see if it is burning/firing correctly by examining what it looks like, if it improves then you know the wire is bad, if it didn't, look further upstream.

I know there is a way to test coil packs, but it escapes me at the moment, but you can do the same trick as the spark plug wire, swap out coil packs with 2 cylinders, the bad one and a good one and see if you can make the other misfire and the known misfiring cylinder, fire. That way you can identify the possibly bad coil pack.

As mentioned, good gas, good air flow, and generally a tune up cannot hurt, however if this problem kinda of came out of nowhere suddenly, then I'd suspect a component failure rather than an issue of improper or poor maintenance.

I gotta read this thread carefully as I may be able to help.  I have a friend who is an old mechanic and his g/f has a 2003 Cavalier and he does all the work on it.  Lemme see what I can do.  I have to ask you first, do you drive it often?  If so, I'm not inclined to think of a fuel problem, but an ignition problem.  If you drive it little, you could have varnish in your fuel system.  See how us old guys think?

To give you an idea of what might be coming, I had a similar problem with my 2005 Neon.  When it was acting-up I could only use a tiny bit of pedal or it would seemingly bog-down from pulling lotsa air and little fuel.  Turned out I needed a new crankshaft position sensor.  Sometimes the timing was right, other times not, depending on the info gathered at the keystart.  And my car had only 52,000 miles.  Yeah, that kind of shiiite can fail now.  Cars are crap now, that's all I can say.  People can crow about high technology in cars all they want, but the thing it brings most is high cost of maintenance!  They are more rust-resistant than when I was young, but you can keep the rest of it, IMHO.

For now I'd say Fry is onto it.  I know an easy way to test an ignition coil.  Connect it to a 12V source of some kind.  While holding both ends of the coil, disconnect one of the power supply wires.  If you get lit-up, it's a good coil!

Hey thanks for all the input guys!  I really appreciate it.  As soon as I get off work tomorrow I am going to get to the plugs.  I did forget to mention that I have the 2.2.  It has been my daily driver aside from whatever days I decided to ride the GS.  I don't change gas stations hardly at all.  I stick to my 2 fav ones unless i get caught low on gas out of town.  I just thought it was odd that it ran just fine 10 min before and then bam!

I guess I will have to go grab me a service manual on my way to work because, surprisingly, I can't find one online.  lol