1996 Saturn SL2 Runs choppy, flashing check engine light

Your on the right tack now. The misfire is the problem you have to get to the bottom of. The plugs and wires are the correct first step.

First of all thank you so much for your donation. If your going to replace the plug's and wire's that's great. Just make sure that you don't put in platinum plug's in they don't run long in that model saturn they carbon fowl.I recommend the ngk standard or bosch super standard plug's they run very well in that model. Also when he has the plug wire's off make sure he replaces one wire at time so he doesn't get the routing mixed up. Also have him check the coil tower's for being corroded where the plug wire's go on real common for that model for that to happen. If it's corroded the coil will have to be cleaned or replaced. Sometimes when you clean the tower's it make's the tower too small and the wire won't stay on and click into place so that's another thing to watch out for. So after you replaced the egr you now only have the P0303?If the plug's and wire's don't fix it we will have to dig deeper. Make the spark plug's are gap at.040" some of the emissions label say.060" which was a error. Let me know what you find.

Let's see what codes you have if you still have a p0303 cylinder 3 missifire then I want you to check spark to that cylinder if you have spark then you will have to rent a compression tester and see what the compression is on that cylinder. Let me know what you find.

If you have a miss even caused by low compression it could smooth out when your on the freeway. We can't assume we have good compression without first checking it there is no way to tell from a woosh. Also I would make sure that you have a injector pulse signal to the number 3 injector. If you want to try replacing the injector that's all on you.I would try swapping the number 3 with the number 2 injector and see if the miss goes to the number 2 before I spent the money on a total shot in the dark. Because replacing the injector is a total shot in the dark.I would check compression on all four cylinder's if you rent a compression tester then I will instruct you how to check compression.I would also get a noid light or a test and check the injector pulse. That's where I would go from here. If you want to try swapping the injector with another cylinder then I would try that but I don't recommend just replacing it.

Glad to hear you got it figured out sorry to hear that it was bad new's. It is most likely a burnt valve that is what I have seen most often. With that many mile's on it I would put it to rest too.I have 213,000 mile's on my 1999 SL2 and it still run's great. If you have any problem's with the new saturn you get you know how to find us. Thanks for using 2carpros.