Auto Zone showed Misfire in #2

3 Weeks ago I turned the ignition but not all the way like I always do. The ingine turned over enough to start and then- it was shaking and the Service engine soon light came one. The shaking went away after 8 minutes. Engine ran normal and the next day Auto zone said I had a misfire in number 2 cylinder.
3 weeks later in did it again. Barely turned over the engine it started. Now running ruff and not going away. Auto zone reported misfire in number 6 cylinder.
I replaced the spark plugs with the ACDelco suggested factory spark plugs- that didn't fix the problem. I knew it wasn't the problem because this only happened when I turned over the engine the way I explained.
I mean I didn't do it on purpose. So does anyone have any suggestions?

HELP!!!!

Don't know what year you have. My 1998 GTX had a ramdom misfire reading. Change plugs and wire. Then went on the hunt for broken wire. Found that between ICM and PCM.
What codes are they giving you?
http://img.photobucket.com/albums/v425/kustomkid54/1998PontiacGrandPrixGTP003.jpg

I have a 2000 3.8 and I didn't get the codes but the person from Auto zone said my computer reported a misfire in #6

Misfires can be caused by a couple things. Bad wire, bad coil even a bad CPU. Need codes. See if they will give them to you.
http://img.photobucket.com/albums/v425/kustomkid54/1998PontiacGrandPrixGTP001.jpg

OK man I'll go again tonight and get the codes. Thanks this is freaking me out...no one wants their baby to run like this and I have a long commute to work, so I want to fix it ASAP.

I got the code for that misfire in #6 cylinder: P0306
I was told by the Auto zone guy that it was the same code for the #2 cylinder misfire

That's not necessarily true. The code will tell you which cylinder. Because it ends in 6, than it's cylinder 6. (Cylinder 2 should be code P0302)

FYI

P0301 through P0310 - Misfire Detection Monitor
The misfire detection monitor is designed to monitor engine misfire and identify the specific cylinder in which the misfire has occurred. Misfire is defined as lack of combustion in a cylinder due to absence of spark, poor fuel metering, poor compression, or any other cause.
Ignition system
Fuel injectors
Running out of fuel
EVAP canister purge valve
Fuel pressure
Evaporative emission system
Base engine
The MIL will blink once per second when a misfire is detected severe enough to cause catalyst damage. If the MIL is on steady state, due to a misfire, this will indicate the threshold for emissions was exceeded and cause the vehicle to fail an inspection and maintenance tailpipe test.

Hey thanks a million CdnLazer That was very educational. I was told it could be the fuel injectors or the coils to name a few. Here is a better description of what I think caused the problem:

I have a 2000 Pontiac Grand Prix with a 3.8L. Three weeks ago I simply turned on my car and it felt like I had a dead cylinder or timing is improper. It went away 5 minutes later. I went straight to Auto zone and the did the free diagnosis. They said there was a misfire in #2 cylinder. I didn't try to fix anything because the problem went away.
3 weeks later when I started my car the problem came back and it's not going away. Auto zone checked it again and there was a misfire in cylinder #6.
I changed the spark plugs and nothing has changed- didn't fix the problem.
What I was trying to say is that I turned the ignition key quickly as opposed to turning the key all the way and holding it momentarily like normal.
Going to get the exact spark plug information too.
Hope that helps!
Thanks

Anybody have an idea as to where I should start? Coil packs or Ijectors?

Ok, a few more questions.

How many kilometers/miles on the car?
When was the last time you cleaned the injectors? (and I don't mean just a fuel injector cleaner - i mean a professional cleaning)
Are the coil packs and wires still stock?
When you take the wires off all the plugs, do you see any corrosion on the ends of the wires?
Did you use di-electric grease when you replaced the plugs?

There are 71,000 miles on the car. I bought the car with 52,000 miles on it
I never cleaned the injectors and I don't know if the previous owner cleaned them
I never changed the wires or coil packs either, I don't know if they are stock
I didn't see any corrosion, in fact, the contacts were very clean
Yes I did use di-electric grease on the plugs

Thanks for the replies!

Ok I fixed the problem> I jumped on top of the engine and tapped all the injectors and so far so good. Running like normal. I tapped them with a small hammer and the #6 cylinder, I couldn't reach so I used a long screwdriver and tapped it with a hammer. I tapped two sides of each injector. Hope that helps anyone out there. Does anyone have any pictures of what the injectors look like?

Does anyone have any pictures of what the injectors look like


http://www.rockauto.com/ref/ACDelco/217-1389.jpg

Thanks
How about a side view of what it looks like in the inside??

A hammer? Isn't that a FORD tool?
http://img.photobucket.com/albums/v425/kustomkid54/1998PontiacGrandPrixGTP001.jpg