And, just to make it more interesting a new code: P0420....

 

You could swap the injector with another one and see if the code moves to the different cylinder.

 

Seems like an awful lot of work. If I take that injector out It would be to replace it, not move it and then put everything back together to see IF the code moves.

 

Pull the number 4 spark plug and recheck it. I've had several get cracked while installing and it could be after it's heated up and expanded and now it's giving you more problems. The insulater is longer than the socket an is very easy to damage

 

The injectors are very expensive. We paid $60 for each of the three injectors that went bad. If you have a multi-meter, you can check the Ohms for each. Use a long screw driver to hear if the injector is opening and closing.

 

I'm thinking these are the original OEM injectors that came from the factory, hence my think of replacing all of them. I've found that cars are like the human body, when they get older, if you mess with one part, other things start going wrong. It upsets some sort of balance.

My thinking on the P0420 code is that due to a bad injector (or two) some raw gas is getting into the cat converter, causing that code to pop up. My biggest fear is that I replace all the injectors, and the stupid thing still runs like crap.

I have a CEL light on the dash that has been there for a while, (goes off every so often, usually during damp weather), and most of the time it isn't generating a code. My ABS light is also on, did so right after I replaced the fuse block. ABS worked fine before, not sure what is causing this.

 

Update: I replaced the coil pack, and the mileage has improved, but not back up to what it was. The coil pack did make an improvement in starting and general power although it never started hard. Still thinking it's an injector problem. I will have to get the CEL situation checked, Hope it;s the upstream oxygen sensor, as the downstream sensor might wind up with a Cat converter replacement=expensive. Wish I could just bypass that whole thing, like I did in my old Chevy van, just replaced the cat converter with a couple of glasspack mufflers and converted the exhaust to dual exhaust...sounded great, and it ran great, too.