Used car advice, codes P3400, P3425 and P0106, engine misfire?

CWILLIAMS336

MEMBER
2008 GMC ENVOY
5.3L
V8
4WD
AUTOMATIC
196,000 MILES

I have owned my car for a year and a half but. Within the last month countless stuff has happened to it. The blend door actuator (passenger side) went bad and had to be replaced. My lifters started ticking for a couple seconds apon start up. There is an exhaust leak and then a misfire (p0307) and (p0172). I also have other check engine lights codes too. P3400, P3425, and P0106. So, is all of this caused by one problem? Or why is my car falling apart all at once? Should I sell my car? If so, what should be my next car? I'm looking for a sedan or coupe under 18k and must be (RWD).

7 Replies

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

At 196k, this car is getting toward the end of its life span. So, the P3400 and P3425 is because of the other codes so these will go away once the problem is fixed.

P0307: Cylinder 7 Misfire Detected

P0172: System Too Rich (Bank 1)

P3400: Cylinder Deactivation System Bank 1
P3425: Cylinder Deactivation System Bank 2

P0106: MAP Sensor Performance

The P0172 code can be because of a leaking fuel injector on cylinder #7, but I would do a compression test to make sure the engine is not hurt, or you can upload a short video of the engine cranking so I can tell what's going on. Ultimately you will need to decide what you want to do and what car you want to buy. Here is a guide to help you with the engine misfire so you can run some tests:

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please go over this guide and get back to us.

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Friday, November 29th, 2024 AT 11:54 AM

CWILLIAMS336

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I looked at the live data and all the cylinders on bank 1 are misfiring. It's just that the 1 3 5 cylinders aren't doing it enough to trigger a code. They have around 60 misfires and cylinder 7 has around 500 misfires.

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Friday, November 29th, 2024 AT 12:13 PM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

This can be because the catalytic converter on that side of the engine can be partially clogged. Here is a guide to help confirm the issue, I marked in red arrows where the cat should be tested.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Check out the images (below). Please let us know what happens.

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Saturday, November 30th, 2024 AT 10:52 AM

CWILLIAMS336

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4 POSTS

I don't think my catalytic converter is clogged. Theres no code for it. And I heard when your catalytic converter gets clogged it won't go past 45MPH. And my car does go past 45.

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Saturday, November 30th, 2024 AT 11:19 AM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

A partial clog can cause the misfire, there are three cats on this vehicle. You said there is an exhaust leak? Where is it leaking? This car has the cylinder delete function which where problems as well which took out the camshaft and lifters.