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Discussion Starter · #1 ·
2/22- car shows P0420 and P0137
- order 2 Oxygen sensors for bank 2 because of P0137 and I seen nicked wires when inspecting Bank 2 Sensor 1
2/23- sensors arrive and since I have work in 2 hrs decide to only change issue sensor.
- after changing sensor car is hesitating and running horrible.
-P0352/P0356 and P0302 show up.
  • move coils around to see if its the issue, coils move but codes still show P0356 and P0352
  • pick up 2 new NGK coils hoping that fixes issue, it does not, all three codes remain.
2/24- Take off air intake, replace both Oxygen sensors in bank 2, remove a coil packs and spark plugs for inspection. Spark plugs are black and fairly new, clean them off. Take off supercharger and clean oil from inside. Check all electrical in engine bay and underneath car, find no issues. Put everything back together and pray. P0356 p0352 still flashing and now P0300 and P0420.
2/25 - call uber for ride to work
  • order otc exhaust gauge
  • if it is cats how should fix? Next exhaust system with high flow cats, oem cats?

Car Is stock and any part i have replaced I've bought oem except two ngk coils packs.
I've notice the exhaust has always had a different smell. Almost like coolant but different. I've always felt the car could run faster than it did and noticed it performed better at times and worst others. Its had a rough idle since I've getting it and no matter what I replaced it never went away. I noticed with everything off there was an oil leak. Not fro. The intake manifold but it looks like its coming from where the heads are. The oil is everywhere underneath vehicle, oil pan, oil filter, trans pan just everywhere and I always smell oil burning. I need mental help after this car.
 

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I wouldn't keep throwing parts at it until you fix the oil leak.
 

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If it didn't run right and smelled when you got it why didn't you address it with where you got it unless you bought from an individual.

If your cat is clogged get headers with high flow cats (If you are concerned with emmissions) or catless. Or hollow out your stock cat.

You need to either fix the oil leak yourself or get it to someone to fix.

For the rest of your issues it might be time to bite the bullet and seek professional help.
 
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^this. I can appreciate you wanting to do stuff yourself, I’m the same way. But I also know my limitations. At a certain point you can’t keep throwing random parts at it hoping it solves the problem
 
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Art Font Cat Rectangle Snout
 
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Let me see I’m understanding. You started getting cat & O2 codes on bank 1 so you ordered and replaced O2 sensors on bank 2. Now you’re getting bank 2 misfire codes.

I haven’t done my sensors but on other GMs the front and rear sensor (one is likely AFM and one O2) have different harness plugs to prevent installing in the wrong position but the ultra cheap crap ones come with no plug and you splice them in. You didn’t happen to buy that type did you?

if it were my ride, I’d throw the old sensors back in bank 2 and see if your misfires go away (and then address the oil leak). Or if you tossed them, swap side to side to see if codes follow.

You said stock so no catch can? The reason I ask is I’ve heard that a misinstalled catch can can cause oil leaks from excessive crankcase pressure.
 

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Discussion Starter · #8 ·
If it didn't run right and smelled when you got it why didn't you address it with where you got it unless you bought from an individual.

If your cat is clogged get headers with high flow cats (If you are concerned with emmissions) or catless. Or hollow out your stock cat.

You need to either fix the oil leak yourself or get it to someone to fix.

For the rest of your issues it might be time to bite the bullet and seek professional help.
Bought it out of state from Texas, 3rd party dealer. Everything was subtle at first. And there was never any check engine light or codes until recent. So I thought the car was fine. Then it suddenly hit all at once.

Let me see I’m understanding. You started getting cat & O2 codes on bank 1 so you ordered and replaced O2 sensors on bank 2. Now you’re getting bank 2 misfire codes.

I haven’t done my sensors but on other GMs the front and rear sensor (one is likely AFM and one O2) have different harness plugs to prevent installing in the wrong position but the ultra cheap crap ones come with no plug and you splice them in. You didn’t happen to buy that type did you?

if it were my ride, I’d throw the old sensors back in bank 2 and see if your misfires go away (and then address the oil leak). Or if you tossed them, swap side to side to see if codes follow.

You said stock so no catch can? The reason I ask is I’ve heard that a misinstalled catch can can cause oil leaks from excessive crankcase pressure.
The oxygen sensors i bought are a gm genuine part from rock auto. I'll post a picture of my codes that came up. 2/23 is after I installed the sensors. And I did swap in the old sensors after the codes came up to see if the sensors were bad. No change. Swapping side to side is a good idea. I will try that.

^this. I can appreciate you wanting to do stuff yourself, I’m the same way. But I also know my limitations. At a certain point you can’t keep throwing random parts at it hoping it solves the problem
I agree but I feel like I've done everything correct. I only bought the sensors because when I inspected them I seen that the downstream sensor had a cut wire which is why I was getting the low voltage on the sensor code. I ran the wires ran the wires the same as the old ones, connected new ones and made sure all connects were tight and no wires were damaged/loose. I've checked all grounds and all are secure. I just bought otc exhaust gauge and am going to check the cats tonight to find out if they are bad or clogged. If none of that works I might have to wave that white flag.

I wouldn't keep throwing parts at it until you fix the oil leak.
Yes, agreed. Thats what my weekend is planned for. I'm just wondering where to look. On top the valve covers are dry but when I took out the supercharger I seen oil near the back of the motor( where the sensors connect). Maybe bad head gaskets. Under the car it looks like the oil is coming from above the oil pan and oil filter and even above the starter.

^this. I can appreciate you wanting to do stuff yourself, I’m the same way. But I also know my limitations. At a certain point you can’t keep throwing random parts at it hoping it solves the problem
I am very hard headed though and I know it's a bad thing that I don't like being told I can't do something. Its very hard to accept defeat.
 

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Discussion Starter · #9 ·
Update: found t
^this. I can appreciate you wanting to do stuff yourself, I’m the same way. But I also know my limitations. At a certain point you can’t keep throwing random parts at it hoping it solves the
^this. I can appreciate you wanting to do stuff yourself, I’m the same way. But I also know my limitations. At a certain point you can’t keep throwing random parts at it hoping it solves the problem
Found the problem
 

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What made you look there?

Did you straighten the pin or replace the ECM?

I assume that is the ECM?

Did your codes go away?
 
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Discussion Starter · #12 ·
What made you look there?

Did you straighten the pin or replace the ECM?

I assume that is the ECM?

Did your codes go away?
Yup, ECM. When I was trying to connect the new oxygen sensor the ecm wires were making it difficult so I disconnected them and cleaned the connection area. Then today when I was on alldata I looked into all my CEL codes that popped up and I looked up the P0356 codes. In that section its mentions "switch the coils and if the issue follows the coils, replace the coil pack. If you move the coils and the issue doesn't follow the coil, replace the ECM" Reading that made me recheck my ECM and there it was.

And yes and CEL are cleared the car is running good. No misfire and not a single code has popped up. And yeah I straightened it out only because I seen no damage to the area that would cause issues and I'm lucky it didn't short out/Destroy my ECM.
 

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Agreed and glad you got it sorted out.

Now find and fix your oil leak!
 
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They might have FIXED it, by ending up charging for a new ecm, but might not have even noticed the pin in the old one.
Ding DIng DING

Winner Winner Chicken Dinner!

That is exactly what they would have probably done and said that the ECM was bad.
 

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Discussion Starter · #17 ·
They might have FIXED it, by ending up charging for a new ecm, but might not have even noticed the pin in the old one.
The Mechanic who used to work on my Subaru did me dirty. I went through 2 engine blocks and 3 transmissions. I ended up selling the car to my good friend who's a mechanic, and when he star
Agreed and glad you got it sorted out.

Now find and fix your oil leak!
I think I know where it's coming from. I have seen a few other threads about leaks coming from the rear main seal. When I took the starter off to trace my leak, I noticed that the gasket looks shot. I checked my valve covers, but they are dry and the oil near the heads looks old and could have been from when my valve covers were leaking in the past. The area's in those rear main seal post are the exact areas I'm seeing fresh oil at.
 

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The ECM pin is EXACTLY why the first place to look is the last place you were.
Many many times, we experience new problems that we actually caused while fixing something else. It also reminds how difficult would be the job of the 'next guy' if you took it to a pro. Even telling him about your changing the O2s, etc, he still wouldn't know or even guess that you pulled the ECM connectors.
 

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The Mechanic who used to work on my Subaru did me dirty. I went through 2 engine blocks and 3 transmissions. I ended up selling the car to my good friend who's a mechanic, and when he star

I think I know where it's coming from. I have seen a few other threads about leaks coming from the rear main seal. When I took the starter off to trace my leak, I noticed that the gasket looks shot. I checked my valve covers, but they are dry and the oil near the heads looks old and could have been from when my valve covers were leaking in the past. The area's in those rear main seal post are the exact areas I'm seeing fresh oil at.
You didn't finish the story of what happened after you sold the car to your buddy.
 
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The area in the top rear of the engine looks exactly like THIS once you move the car out of the way so you can see.
Maybe that will help you chase the oil leak.
Note that there is an oil pressure sensor that can also present a leak from the threads or the sensor head.



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