01 Cavalier Engine concerns.

Hello everyone, I am new to this forum and forums in general so I apologize if this topic has been gone over time after time but I would greatly appreciate some advice and wisdom. I just recently purchased a 2001 Z24 Cavalier equip with a 2.4L motor. I purchased the vehicle hoping to take full advantage of the fuel economy. The vehicle is a 5 speed manual and is a blast to drive in the snow here in Michigan.

Unfortunately when the vehicle was purchased there was a misfire present at idle only but not while actually driving so I figured being as I was a mechanic for several years, then a body technician I would take on the challenge being as the price was very low. Under $400 dollars low.

With all that being said after getting the vehicle home I put a scanner to it and to my gut wrenching surprise there where 11 codes present. I pulled the codes and addressed them as I saw fit and believed I could fix the vehicle fairly easily. Unfortunately I have proven myself wrong thus far and am hoping someone has an answer or thought as to lead me in the right direction towards a solution.

I ended up replacing the spark plugs (they were in dire need as they appeared to be original) "the vehicle has close to 200K on it".

I replaced two coil packs (One appeared cracked, the other rusty)

I replaced the coil pack housing (which was brittle and stress cracked)

I replaced the coil boots (or spark plug boots?)

I also decided to replace the air filter and change the oil as I always do when I purchase a new to me vehicle.

Of course all the codes where erased before restarting the vehicle and when I did restart the vehicle to my surprise there was absolutely no difference in specifically the idle of the vehicle. I hooked the scanner back up to the vehicle and It went from having 11 codes to only 4.

The codes are as follows P0453 (evaporative emissions control system pressure sensor high output), P0300 (which shows on the scanner twice) (Random Multiple Misfire), and P0480 (Cooling Fan 1 control circuit malfunction).

My concern is that while experiencing the irregular idle there is clearly oil being burned as you can see blue smoke from the tail pipe. But when you bring the vehicle to around 1400 rpms the smoke stops and clears up. I have tried to find resolution through internet searches and have not seemed to find an answer. I did decide to further try repairing the vehicle by checking the IAC sensor which was clearly original so for lack of a better term and I know this is not how to properly diagnose a vehicle but frustration set in so I started to throw parts at it. I replaced the IAC sensor and yet again no change.

This is where I began to really be confused. I decided maybe the battery in the vehicle was bad because it was not displaying the recommended voltage or CCA's so I swapped the battery with another car I had. Codes still present the car started and no rough idle ( I was excited) and then not a minute later the vehicle began to miss and idle like crap yet again. So my thoughts are that corrosion is present in the battery cables, could this be my misfire problem as the battery is not working properly with the alternator to keep this electrical system running properly? I also was looking for a PCV valve but could not locate it on the motor thinking that could be my burning of oil problem.

All in all I do have mechanical knowledge but have allot to learn when it comes to this particular motor. It is humbling and frustrating all at the same time. I apologize for the long post, and again if this topic has been brought up several times. I am new to the forum world and have to learn the ins and outs.

Anyone with information I would greatly appreciate it, I need to be schooled when it comes to this motor. And if anyone has pictures of possible problem areas I would appreciate seeing those as well.

Thanks again for the help, Happy New Years to all.

Can you still feel a misfire at idle? Many GM vehicles won't show a P030(1-8) code unless it's a very pronounced misfire that's been going on for quite a while. You'll probably need a scan tool that can display misfire data, just look and see which one(s) show not zero. If one is a very high number and the one after it in the firing order shows roughly 10% or less as many as the main one, the PCM *may* be showing that one erroneously. IIRC, it's 1-3-4-2 on these. I think it is stamped somewhere on the big cover thing that has the coils attached to it or maybe on one of the cam covers. I know I've seen it while doing plugs in these.

P0453 will require dropping the fuel tank for a complete test, unless you really want that light out, I'd let that one go.

P0480 will probably be a bad fan motor. Check the fuse for the fan, if it's blown, unplug the fan connector and run the engine to just past where it should turn on, 222º if you can see data on your code checker. Or jumper the fan relay if you know how to do that (pick the wrong terminal(s) and you can fry the PCM). Install a new fuse, if the fuse doesn't blow, plug the connector back in. If the fuse then blows, the fan is bad.

Yes, I can still feel the misfire at idle but it is not as noticeable as it was and for some strange reason it no longer burns oil or blows Blue smoke. I took the intake off and cleaned the crankshaft vent case which had signs of condensation in it. (I have read this is common sometimes in winter months). I also put two new hoses on the crankshaft vent case. The P0300 code is still present at this time but seems to run better every time i turn the car on. So im baffled on that issue.
I can live with the P0453 code, its not worth worrying about in my opinion based off of what I have read its common and most people let it go with no underlying issues.
As far as the P0480 code you are absolutely right. I put a new cooling fan motor in and that problem went away.

I am really confused with this P0300 code, Its strange that I havent been able to pinpoint the issue. I have talked with several reputable shops around my town. I have known allot of them since I was a kid and they say These 2.4Ls are notorious for issues. I really appreciate you replying. I will take into consideration your advice and give it a shot! Thank you again.