New motor no power

SOMEGUY4469

MEMBER
1997 GMC YUKON
5.7L
V8
4WD
AUTOMATIC
108 MILES

Hi, okay, I had my truck parked for awhile one day wouldn't start took it to a shop he said it's wired completely wrong and rewired it got it going. It started to bog really bad like it was plugged somehow. I had the motor replaced. Got burned on that and ended up having it replaced under warranty. Drove it and it's the exact same thing that was happening before it's like it's plugged. Any ideas?

Friday, July 26th, 2019 AT 10:33 AM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Welcome to 2CarPros.

When you have a power loss like this, the most common cause is a plugged catalytic converter. If the engine can not properly exhaust, it builds back pressure and you have a big power loss. Interestingly, you described it as feeling like it is plugged.

Here are a few links I want you to look through. The first describes symptoms associated with a plugged converter. The second and third describe hot to test a converter and replace one. Check that first and let me know what you find.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

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

https://www.2carpros.com/articles/catalytic-converter-replacement

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If you are able to, remove the pre catalytic converter sensor and see if it makes a difference. Because of the size of the sensor, it won't feel perfect, but you should notice a difference.

Let me know what you find or if you have other questions.

Take care,
Joe

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Friday, July 26th, 2019 AT 8:21 PM