I have a 2006 Mazda 3 2.3L engine with OBD II readings that I need help troubleshooting.

Problems: Sputtering, riding rough, poor gas mileage, overheating off/on
Codes: p304, 401, 441 455, 2177, 2407, 304, 841

Fixes so far: Change spark plugs, change ignition coils, replaced valve cover, cleaned MAF sensor (both in tube/and temp wand) changed oil, flushed radiator, replaced hose and water outlet, replace top pass engine mount

This has nothing to do with engine, I think (?), had the problems prior and after this work - changed control arms, inner outer tie rods, sway bar links - Now, after this , there was a whirling sound (I say it sounds like the passenger side, the passenger says it sounds like the drivers side)... kinda like a plane engine revving up. It gets louder the faster I drive. Just a side question - what should I look at to diagnose this noise? It's only when the car is moving so...

After fixes, continuing problems: riding rough, overheated after running 2 miles turned on a/c dropped immediately then hasn't gone back up again (drove another 25 miles).
Codes P2177

Attaching last readings in a Excel spreadsheet from Torque app (you can open with Google Sheets).

Questions:

• In this spreadsheet, EGR has sporadic readings and drops to 0 (I don't know if this is normal?)
• CAT spiked to 1495*F, but then second drive (don't have spreadsheet) it stayed at about 700*F.
• Previous owner looks as if he went mudding with this car. The entire bottom of the car was caked with mud. I've sprayed as much as I coud off and a chunk of dirt fell out of the second cat (shield?)
• Not showing a CAT Bank 1 Sensor 2 (not sure if it's the app or if there isn't one?)
• Timing Advance normal(?)
• Bad Battery(?)
• Bad EGR(?)
• Bad PCV or hose(?)
• Any recommendations to check each of these before taking the entire engine and exhaust apart?

 

I Removed my response because after I posted you added and changed your first post (time time line editing) therefore parts of my response was based on your unedited response.

Good Luck

 

Yes, and you passed! Thank you for the feedback!

Some of the work was performed after I discovered oil in the spark plug wells (Sorry, I forgot I had replaced the valve cover and cleaned out the wells).
I decided to replace the coils at that time (200k mi. on it).
There was a leak in water outlet (plastic crap,replaced w/metal) and engine mount was leaking oil.
Also, due to Covid, I have only drove the car up and back to the store about 1 mi., and there was some carbon fouling on the plugs and the MAF sensor cleaning was recommended.

I cleared the codes, and let the car idle for 20 min w/o a/c or anything else running, then 20 min w/a/c running full blast to reset timing after cleaning the MAF sensor.
No codes until after driving for about 30 min. until... P2177