2001, Engine Vibration (missing badly), Flashing CEL

Looks like there is no egr on the Gen 1. Someone please correct me if I'm wrong.

 

Updates: swapping coil packs between cyls 1 and 4 didn't change anything. Still code 0304 after resetting. Plugs look ok, brown deposits.

I'm now worried that it's not an engine issue at all. Now, after the troubleshooting described above, it is acting weirder. When I first start it, it runs ok, then within 15 or 20 seconds, it starts shaking and rattling badly, and the ABS light came on.
What makes me think it's not the engine, is that, when the vibration/rattling starts, the car seems to want to lurch forward a bit, even though it's in park. That's bad, right? PSD?

 

Because this car lives at the metro station, far from my home, it is difficult to find time to troubleshoot. So I have decided to go ahead and replace all the plugs and ignition coils, just to eliminate those as a possibility. Parts are ordered, but won't be here until after the weekend. Something changed after swapping the #1 and #4 coils, because it started shaking much worse. Perhaps it is now missing badly on two cylinders, instead of just one.

If the ignition parts aren't the problem, the next step will be the injectors. What is involved in getting to those?

Thanks,

 

Nope, because the car isn't at home, I'm having to do this diagnosis a few minutes at a time on my way to/from work. I will (hopefully) eliminate ignition issues tomorrow (either eliminate the problem, or eliminate the ignition as the cause of the problem) by replacing all the coils and plugs. No, that's probably not the cheapest way to go about it, but its the way that lets me move the troubleshooting along more quickly, and with fewer trips back and forth to the car. The coils have several hundred thousand miles on them, so I don't feel to bad about the money spent, and the plugs are cheap, so I don't mind replacing them either while I'm at it.

This car is by far, the cheapest car, per operated mile, that I have ever owned. If I have to spend a few hundred dollars either fixing it, or making sure it is really beyond hope, I am fine with that.

Thanks for your help and suggestions.

 

I replaced all 4 coils and plugs this morning, and so far, so good. It ran well on the way into the office this morning. That may not mean anything since it was an intermittent problem. It is definitely much better than when I left it on monday, and I think I know why. When I replaced the #4 plug today, I found the rubber "thingy" from the inside of the spark plug wrench still on the old plug that I reinstalled on Monday. I think it was preventing the coil on that cylinder from contacting the plug. So that cylinder probably wasn't firing at all, and making the shaking and rattling much worse than it had been.

So its either "all good" now, or I am just back to the intermittent state I was before Monday. I'll update this thread either way when I find out.

 

Well, the coils and plugs didn't fix it. It started missing on the way back to the station from work on Friday. I hadn't been back to the car until this morning. I pulled the codes, and it is showing P300, P303 and P304 codes.

My next step was going to be replacing all the fuel injectors. Before I do that, How do you check the fuel pressure?

 

Anybody know of a good set of instructions or youtube video explaining how to replace the injectors? Thanks,