To begin, my car is actually a Saturn LW2 3.0 V6, but this website does not offer that selection. A couple days ago, I was driving home from PA to FL. I drove through some pretty heavy snow. After a little over an hour of driving, I came to a stop sign. When I began to accelerate, the car had little power and the check engine light came on. It was also very shaky, especially when either idling or accelerating. I drove it to the nearest auto parts store to get a computer scan. While they would not give me a print out, but the error codes said something about Cylinder 2 Misfire detected and also another code which said EGR valve defective (Or something like this). They advised me to visit their competitor, who would give me a computer scan print out. The second scan only revealed one code, which is P0302. The Definition is - "Cyclinder number 2 misfire". Explanations was "The powertrain control module monitors the crankshaft speed and has detected a misfire condition." Probable causes were "1. Ignitions system fault - spark plugs, ignition wires, coil or 2. Vacuum leak or 3. Injector fault or 4. High or low fuel pressure." The second store did not find any code about the EGR valve. Because the snow was heavy and it was getting dark, and I had several hours to drive to get to a hotel, they recommended trying some Fuel Injector Cleaner. I used the Lucas Complete Fuel Treatment. After driving another 20 Miles or so, I pulled over again, and after restarting the car, the problem disappeared. (NOTE THE PROBLEM ONLY DISAPPEARED AFTER RESTARTING CAR). The check engine light remained on. Eventually, the check engine light went away, and I was able to finish my drive home to FL.
So, I say all that to say this- I will begin traveling again in about 4 days, and I would like to see what your thoughts were on this car problem. The spark plugs are new and were installed about 3000 Miles ago. Same for the fuel filter. While I am thankful the problem disappeared long enough for me to drive home, I am not convinced that the problem was the fuel injectors and I'm not assured the problem will not reappear. I use fuel injector cleaners occasionally, so I don't think the fuel injectors would be the problem. And also, the problem disappeared after turning the car off and on a few times. Another thought is, could it be possible that the problem is related to the very heavy snow I was driving through? There was icicles and ice buildup all over my car. Please let me know what you think!
Were the codes cleared by the first person that checked them or the second person?
February, 19, 2013 AT 8:56 PM
I am not sure if either of them cleared the codes, or if they just eventually cleared out after restarting the car a few times.(I guess?)
February, 20, 2013 AT 4:55 AM
A lot of the diyer scan tools won't read history codes so there could be some history codes.A egr issue could cause miss fire code's.
February, 20, 2013 AT 4:48 PM
After doing a little research, I have seen that a clogged or dirty EGR valve can cause engine misfire. Today, I will take it off and see if it needs cleaning. If it is the EGR valve getting stuck or something like that, would it affect one cylinder only or all of them randomly? The only code I got was for cylinder two, which makes me think it could be something else.
February, 20, 2013 AT 5:52 PM
Well, I took off the EGR valve and examined it. Admittedly, I don't know exactly what all I am looking for. I have watched a video or two on how to clean an EGR valve. However, it appeared quite clean with no carbon build-up. The "plunger" part of it opened and closed freely when pressed. I understand there may be other problems with it, but it does not seem dirty and does not seem that there is any build-up that would hinder it's ability to open or close the airflow. In fact, it was surprisingly clean.
February, 21, 2013 AT 1:27 AM
How does it run right now? Can you feel it miss while driving?
February, 21, 2013 AT 2:03 AM
Well, once I got out of the very thick snow and restarted my car a few times, the problem went away. I have driven about 800 miles since then, and the check engine light has not come on since then. For the most part, the car has run well. When I started the car this morning, it was a bit shaky as if there was a misfire, but it went away fairly quickly. My wife told me it also did that yesterday as well. So, while the problem seems to be in hiding, I am not convinced that it won't come back. I travel for a living, so I'm really hoping it doesn't mess up on me again. Unfortunately, I'm beginning to think I might not be able to identify it until it gives me more problems. Only problem is, I might be in the middle of nowhere when that happens. Thank you for all of your help thus far. If you have any suggestions, please let me know. Otherwise, I will keep you posted if I get more problems.
February, 21, 2013 AT 8:41 PM
Let's try this get some good fuel injector cleaner some chervon techron cleaner the expensive stuff and fill your tank with some chevron gas. Drive the tank let me know how it runs. Dirty injectors can cause random miss fires etc.
March, 1, 2013 AT 11:36 PM
Well, I tried some more fuel injector cleaner, but I still had to occasional shaky engine due to cylinder misfire. This happened on and off a good bit over the last week or so. Today, I had a good opportunity to take it to a mechanic shop. He hooked up the Snap-on diagnostic machine and noticed that nearly all of the misfires were located on cylinders 2, 4, and 6. There were only a few on any of the other cylinders. This really seemed to point to the Ignition coil being the cause. Today, the ignition coil was replaced, and so far so good. Time will tell if this was the problem or not.