Completely puzzled on air/fuel codes.

[DaveRad]

98 62k miles
What I’ve already replaced over the last year
- MAF
- AOS
- Coolant
- Spark Plugs
- Oil Filler Tube

I get different codes every time the CEL comes on, but today some new codes came up.

The current codes I have are:

P0430
P0410
P1411

Pending codes:

P1129
P1127

I usually have P1124 and P1126. When I remove the oil cap, it runs rough for about 4 seconds, then steady idles at 950 or so.

I’ve done a smoke test through the intake and I couldn’t find any leaks. Here are my current CAT readings

Bank 2, I’m giving it a bit gas so about 1,750 rpm’s


Bank 2, idle


Bank 1, 1750 rpm


Bank 1 idle

[stateofidleness]

Any smoke on startup? Could be AOS replacement time.

[JFP in PA]

P0410: Secondary air injection signal implausible, bank #1
P1411: " bank #2
P0430: Main cat conversion too low, bank #2

P1127: Mixture is so rich that the DME cannot compensate, bank #1
P1129: " bank #2

[Homeoboxter]

You have multiple things going on. P0410 and 1411 are both for the SAI system and not related to the others. I would tackle these separately and try to address these once all the others are resolved.

Your O2 sensor signals may suggest that both cats are close to the end of their lifetime, the post-cat signal should not follow the pre-cat signal like that. Post-cat signal should be more or less flat. The O2 signals at idle are confusing though... are you sure the tool was connected? The pre-cat sensor's signal should be oscillatong between 0 and 1, and if not doing that it should throw a separate code for sensor malfunction or signal interruption. I can't see those codes in your list. The mixture richness may be due to a leaking injector or some vacuum leak. I'd clear all codes and see which one comes back and when.