Billu99tl

hello All. I dont usually post Mechanical questions as I can get them fixed locally. I have a small issue with my car 08 Type S which have ATLP Exhaust and have 140K Miles . Check engine light is on since exhaust was installed. I was told that it needs some sort of magnaflow resignator.2bgndf
I got these 4 P2628 codes on the car P0404 P0430 P 0135, and according to my mechanic first I had to replace my Rear Upstream A/f Sensor. I just replaced it with oem part.

Problem is i have to send the car to new york and it have to pass emmisions there. I searched internet and all bunch of different info I am getting. 1 excellent mechanic shop down in miami inspected the car and told me i have to replace Catalist Converter by the Engine one told me by the exhaust.

Only simptons I am getting is that car runs really well on normal driving but if i drive it for 30 minutes -1-2 hours and park it turn it off and turn it back on it takes 3 seconds for self and start and black smoke just very very tiny bit comes out of exaust. Its been like this from long time.

Please If someone with knowledge tell me what part i have to buy and replace and i can get it done ASAP to make this car perfect as I dont want new buyer to have any issues at all to pass inspections.
Thank you so much

dcolucci7

There are a few things you can check, but first off. Does the car begin to have performance issues after its heated up? Such as small lack in power or seems to shirt late? If so, this could be related to a plugged cat. Most mechanics can take an O2 out and peek in with a camera to see if the cat is plugging up or damaged. If its not the cat, there may be a few other possible issues. Electrical or mechanical. Electrical can sometimes be easier to find. Usually you need some type of scanner that can check OBD2 status. After clearing the codes, it should take some time to complete the on board test for cat efficiency. If a code comes back immediately, it is usually related to a electrical fault either in the sensor related to that code (IE O2 b1s1 would be a fault with O2 sensor bank 1 sensor 1) If no code, check the voltage output from the OBD2 reader and see if the O2 sensors are reading within range and sweeping up and down smoothly. There may be a dead sensor. You had an O2 heater code witch is usually an immediate fault code related to a bad sensor or bad wire.
Since you have an aftermarket exhaust. There is a chance that O2 wiring was altered in routing or extended. A butt connector may have been bad or the rerouting could have the wire melted across the exhaust.
There is a chance that your throttle position sensor is bad as well. This can sometimes be monitored through OBD2 but intermittent issues are hard to pick up because of how fast they occur, but ultimately, the computer misjudging the throttle, could feed the engine odd fuel mixtures giving your O2s skewed readings.
On the mechanical side, things could get bad. Hopefully you can narrow the issue down to a single engine bank. One issue could be a bad valve. With high mileage, your valves should be adjusted. Otherwise, god forbid, you have a bent, cracked, leaky valve or head.
Another not so bad mechanical issue would be an exhaust leak. (cracked manifold, gasket) This will skew O2s as well. Making the computer feel lean and richen the mixture.
One of my last but not so uncommon guesses would be a bad injector. They arent always completely bad, so you wont have a misfire, but it could be a leaky or clogged injector. The best way to determine this is pull the plugs and find if a plug is different than the others, which reminds me that you could also have a bad plug, plug wire, or coil.

Anywho. Good luck