Engine is misfiring?

Clynders 2 and 3 are not firing

Been running great until yesterday, misfiring badly, a friends scan tool showed cyl.2 &3 misfiring, replaced coil pack and now have only slight miss but seems to be running very rich, anyone have any ideas.

Swap #2 and #3 injectors with #1 and #4. If the injectors are bad you will get a misfire on #1 and #4 cylinders.

Have your ignition module tested, and check the spark plugs.

I have a cylinder misfire.
Furthermore the sound coming from my muffler is altered.
The car fells like it is bogging down.
Engine is shaking as if I were in a high gear driving too slow.
Also right after I step on the clutch most of the time idle speed is temporarily drops to about 500rpm.

The problem is not
-compression
-fuel injector
-spark plugs
-coil pack

I had a mech check back pressure in the exhaust system he said that was fine, but the new mech I have it at wants to check it again.
It has been a month now that I do not have my car and all the mech I take it to think the problem is one thing only to find out they are wrong. The current mech I have it at is going to give up shortly and set my own my way with a bill and no result.

What do you think the problem is?
I could use all the help I can get. Thank you

You might check the coil pack housing and ignition module. I recently had a misfire problem, would hardly run at all, wasn't driveable.
I changed the coils and spark plugs, the problem persisted. I finally took it to a mechanic and the coil housing was the problem. I know you listed coil and plugs as not the problem, just a posibility you might check. I have a 97 2.4, not sure how much the ignition system has changed.

I changed the coil pack and the plugs.
I will have to try the housing and the plugs boots.
My mech just handed me my car back and said he cann't fix it and for me to put it on a computer, but it would be costly.

Did you ever figure out a solution. I believe I am having a similar problem. Mine doesn't always do it though, it just depends. Sometimes when it does misfire, if I turn off the car and then turn it back on it works fine. I have replaced the plugs and cleaned the full injection system. Thanks for any help.

I'am having the exact same problem and was also wondering if you have found a cure to your problem.

Had the same problem listed above. Changed out the spark plugs and tried the coil packs, but the problem persisted. Tried the coil pack housing on a whim because of a previous reply on this thread and it worked! I also have a '97 2.4L Cavalier. Hope this helps!

I have a 99 2.4L Cavalier and had the same problem. Change the housing around the coil packs first. After changing out many part, the check engine light went off and fixed it. However a few weeks later it's doing the same thing. Now I just need to find out WHY it is going out.

I have a 2003 Cavalier just put new plugs and boots on it. Ran perfect till motor warmed up then was misfiring again. It comes cylinder 3 again as was before replaced the plugs. It also had a code P0440 EVAP System No Flow During Purge. Can you please help me on where to start I also put a new gas cap on it.

Thank you