2006 RX8 automatic, 101k miles factory engine

Last night after driving for a good 25 minutes, about a half mile from my house my engine started struggling going up a hill. My RPMs wouldn't go higher than 3k even when I shifted in manual, and it felt like I was on a roller coaster with how shaky it was. Previously it was idling pretty rough and stalled when in park (but not drive), so I had been using it fairly regularly assuming the only code I had was for my o2 sensor. I got one of the O2 sensors Installed after I had a P0032 code, and I have had the other one waiting until I can rent out a lift station since we need to remove the exhaust manifold.

I got home, turned the car off, and went to bed. I attempted to start it up once this morning and I got a bunch of popping before I decided not to push it. Just diagnosed all of the new codes. I bought my RX8 on a bit of a gamble budget so I only have ~$700 to spend on repairs at the moment. I'm beginning to think that this engine just needs a rebuild and that I might be better off selling for a commuter (I don't want to do, but I need to get to work somehow).

Here are the codes:

P2004 - Variable tumbler valve stuck open

P0302 - Cylinder 2 misfire [Marked Severe]

P2096 - Target AF feedback system too lean right bank [Marked Severe]

P2259 - Secondary air injection system control 'B' circuit low


If any of these are relatively cheap to fix please let me know or link a related thread.

Any and all help is appreciated, I would hate for my stay in this community to be so short.

 

Typically these engines last anywhere from 70k miles to 140k miles depending on how it has been treated from the factory.

The main cause of death is loss of compression due to the seals wearing down. Signs of low compression usually follow issues of:
-slow hot starts
-not hot starting at all (potentially flooding)
-not hot starting and eventually rough idle
-eventual searching idle between 750 and 1250rpm
-wont idle and dies under around 1000 rpm (easy to stall)
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That being said it seems like you have some other issue that involves either the ignition, fuel, or the O2 sensors. Keep in mind the rear o2 sensor has no impact on performance and is used for the emissions+catalytic converter. I'm, sure others will chime in to help diagnose further.

 

if it has a cat converter in the exhaust system then you might check to see if it became clogged/broke up

P2004 is the APV intake valve stuck open, so that’s not going to help low rpm power or idling.

a clogged catalytic converter will contribute to most of those other things, but it will also ruin an engine pretty fast. I’d check that first.

it might need a rebuild any way, but might be able to put it off longer it it’s just the exhaust blocked up.

 

I’ll check the cat converter tonight or tomorrow. That sounds promising. Thanks.

 

Misfire could also be MAF if your cat is still in good shape or already hollowed out. I've solved misfires just cleaning it and putting it back in. Could also be the ESPS sensor by the crank pulley is dirty. Couple cans of MAF and Contact cleaner can make a world of difference. It's likely not the engine but you can do a compression test to be 100% sure.