97 codes need fix

P0404 = EGR Circuit (Closed valve Fault) P0301 = Engine Misfire Detected in Cylinder 1 P1133 = Oxygen Sensor (Too few switches)

When was the vehicle last tuned? How many miles? Did it just start acting up or has the service engine soon light been on for some time? If it just started, was any work done to it recently?

I'd start with the basics since they are cheap: (1) New properly gapped

0.40" OEM spark plugs, (2) New ignition wires if these are more than a couple years old (make sure they are routed properly), and 3) a good fuel injector cleaner (e.g. Techron).

If this does not fix it, I'd take a look at the ignition coil tower. This can be easily removed (4 bolts) and then the connectors can be cleaned with a wire brush and some sandpaper. Make sure the engine block under the base, the base plate, and the bolt holes are also clean and shiny since they provide ground for the unit. (These can have a lot of corrosion preventing good spark and possibly causing the misfire on cylinder #1.)

If you still have a problem, you can then try popping the fuel injectors at the connector and making sure they are all clean and tight. I've personally seen simply reseating a fuel injector connector solve a misfire on this engine.

If still no luck, then you might try to remove and clean the EGR valve. The gasket is cheap and should be replaced when you do this.

As a last resort or if the P1133 code remains, you can try to replace the O2 sensor.

Good Luck!

Bob

Note: gap on plugs should be 0.040" Sorry about the typo...

thanks for the info

The mileage helps, but you do not indicate when the plugs were last replaced or the wires. My guess is that you will also definitely need to remove and at the minimum clean (worst case replace) the EGR valve.

As background, my son's '96 Saturn 1.9L had 115K miles when the EGR failed. When I removed it it was pretty coked up in the passageway and was definitely sticking. I used a small flat blade screwdriver to chip most of the stuff out and then used a small dermal tool with a wire brush attachment to polish up inside there as best I could. When I was done I used some throttle body cleaner to dissolve whatever else might have been in there. When I was done I cleaned the passage ways to the intake and exhaust manifolds with a small "battery" type wire brush (for cleaning inside the battery clamp). The EGR valve operated manually beautifully when I was done and everything was pretty clean. The new gasket cost us about $3 and when we put it all back together it worked fine and the code (different from yours, but my guess is your EGR is so bad it won't operate at all any more) disappeared.

My point here is the EGR is pretty simple to remove and may be reusable. He has subsequently driven the car for about 1 1/2 years without this re-occurring.

My last thought here is if it has not been done lately, replace the PCV valve since these have a tendency to clog and can cause oil burning which can cause spark plug fouling and accelerate the EGR problem.

Good luck. Most everything I've suggested here is low cost and easy to do yourself.

Bob

PS The fuel and air filters are other things which should be changed regularly. The air filter is a breeze to change, but the fuel filter can be difficult due to its location.