P0302 Saturn - 2000 SL1 stalling at light. P0302 and P0410 code found with CEL test.

Question

I have a 2000 Saturn SL1 that has been stalling randomly when I'm at a light. Also when I'm driving on the highway sometimes when I brake it will stay at that RPM and rarely it has even gone higher for a second as if I was revving the engine! I think it has a low idle (hovers around 600 RPM. It had a CEL with the codes P0130 (O2 Sensor Circuit Malfunction Bank 1 Sensor 1.) and P0410 - Secondary Air Injection System Malfunction.

I replaced the O2 sensor and had the light reset. It came back on a few hours later and when I got it checked the same lights were on along with three more:
P0300- random multiple misfire
P0302- Cylinder 2 misfire
P0133- HO2S Slow Response Bank 1 Sensor 1

I replaced the spark plugs, wires, and coils, and reset the light and I still got the codes for the cylinder 2 misfire, and secondary air injection system.

Couple weeks later got it checked again and had the same codes show up but this time it took around two days for the CEL to come back on. This time it only had the secondary air injection code pop up.

One mechanic said my catalytic converter could be clogged. Another said I might not be getting proper compression.
My question is could the cylinder 2 misfire have taken those two weeks to correct itself after I replaced the spark plugs, wires, and coils (which didn’t look all that bad)? Why would the O2 sensor code come up right after replacing it?
Any help would be greatly appreciated. Thanks.

Answer 1

P0300 Random misfire

P0302 Misfire number 2 cylinder

P0133Oxygen sensor slow response Bank 1 Sensor 1

Low idle RPM, Saturns RPM is set at 750 - 800 RPM in nuetral or Park and you have 600RPM this is a low RPM , with a misifre on the number 2 cylinder. First understand what a normal 02 sensor would look like or respond like.

 Here is a normal 02 sensor wave form, this is 4 cylinder GM product. with a good RPM and no misfire , this engine is in fuel control.

 Here is a slow 02 sensor or a P0133, this is the same vehicle but with a fuel injector disabled. and due to the misfire the RPM went low also.

The best way to resolve the issue is to find out what the cause of the misfire for number 2 cylinder is. You already did sparkplugs, the sparkplug wires, and ignition coil. So this leaves you with a fuel injector or a mechaincal condition , a good compression test or a leakdown test would help identify the problem

Answer 2

P0300 Random misfire

P0302 Misfire number 2 cylinder

P0133Oxygen sensor slow response Bank 1 Sensor 1

Low idle RPM, Saturns RPM is set at 750 - 800 RPM in nuetral or Park and you have 600RPM this is a low RPM , with a misifre on the number 2 cylinder. First understand what a normal 02 sensor would look like or respond like.

 Here is a normal 02 sensor wave form, this is 4 cylinder GM product. with a good RPM and no misfire , this engine is in fuel control.

 Here is a slow 02 sensor or a P0133, this is the same vehicle but with a fuel injector disabled. and due to the misfire the RPM went low also.

The best way to resolve the issue is to find out what the cause of the misfire for number 2 cylinder is. You already did sparkplugs, the sparkplug wires, and ignition coil. So this leaves you with a fuel injector or a mechaincal condition , a good compression test or a leakdown test would help identify the problem