Engine low power

Tiny
TOPHER SAVERANCE
  • MEMBER
  • 1995 CHEVROLET 2500
  • 7.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
My truck does not want to shift to third or overdrive gear. When I give it gas it wants to bog down and does not get over 20 mph.
Saturday, January 12th, 2019 AT 10:49 AM

6 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,782 POSTS
Hello,

It sounds like you have a plugged catalytic converter. but to be sure here is a guide to help us check:

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

Please run down this guide and report back.
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Sunday, January 13th, 2019 AT 11:08 AM
Tiny
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Thank you. I didn't think of that. But here is another question why would my truck not shift into third or over drive gear? I replaced the shift sensor would the catalytic converter cause that problem too?
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Monday, January 14th, 2019 AT 12:49 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,782 POSTS
Sorry, I should have explained it better. With a clogged catalytic converter it lowers the vacuum so the computer think the truck is under extreme load which backs the shift points up. Please run down the guide to see if that helps. I would disconnect the exhaust and drive it to see how the power and shift point change.
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Monday, January 14th, 2019 AT 9:34 AM
Tiny
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Okay, I'll try it.
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Monday, January 14th, 2019 AT 10:07 AM
Tiny
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What if I run it to red line and then it still does not want to shift?
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Monday, January 14th, 2019 AT 10:28 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,782 POSTS
Did you have the exhaust disconnected? If so lets run the codes to see what come up.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.
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Tuesday, January 15th, 2019 AT 10:10 AM

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