1990 Chevrolet Trailblazer Vibration

1990 CHEVROLET TRAILBLAZER
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WARLOCK
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  • 1 POST
I have a 90' full size Blazer - 145,000mi. Whenever i accelerate the whole truck seems to vibrate. When i let off on the gas the vibrating goes away and is a smooth ride. When ideling the motor is very responsive and smooth. I have replaced the plugs, rotor, distributor cap, pcv valve, fuel filter,oil and filter change. Fuel pump seems to be working fine, the truck never wants to stall out. It does idle a bit high, but the idle adjustment screw is snapped off and i have not yet replaced it. Someone please help..... :shock:
Feb 6, 2006 at 12:01 PM
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SQM
  • ✓Experienced Mechanic
  • 6,383 POSTS
Hello,

This issue sounds like a drive shaft issue.
It could be a number of things on the drive/prop shaft that can go bad.
It could have a faulty U-Joint, loose/weak yoke, it can also be due to an out of balance or bent drive shaft.

The best course of action would be to do a thorough inspection of the drive shaft and look for any lose or damaged components.

https://www.2carpros.com/articles/how-to-remove-a-drive-shaft
https://www.2carpros.com/articles/how-u-joints-work

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.
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Jan 14, 2022 at 1:03 PM

Suggested Repair

Thoroughly inspect the driveshaft for a faulty U-joint, loose or weak yoke, or a bent or out-of-balance shaft, and repair or replace any loose or damaged components.

Conversation Summary

The owner of a 1990 full-size Blazer with 145,000 miles reports vibration while accelerating that stops when the throttle is released. Idle is smooth, and the plugs, rotor, distributor cap, PCV valve, fuel filter, and oil and filter have already been replaced. The expert attributes the symptom to a possible driveshaft problem, such as a bad U-joint, loose or weak yoke, or bent or unbalanced shaft, and recommends a thorough driveshaft inspection.

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