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Engine Shudders / Burning Rubber Smell

Car Details: 2004 Olds Alero GL, 250K miles, well maintained.

Our car recently started shuddering/vibrating at speeds over 45mph. Once the shudder begins, it continues for the remainder of the drive. It doesn’t feel like it’s in the wheels or the steering column, and there are no warning lights on the dash. It seems to be more intense when braking, as if something were fighting the inertia of the vehicle. There’s no difference in the sensation when driving around corners.

After a few minutes of driving, there seems to be a burning rubber smell that is concentrated near the windshield in front of the driver’s seat. I have no idea if this is related, but I suspect that something is damaging a hose with heat or friction. I’ll be taking it in to a mechanic, but I’d like to have an idea of some of the possibilities before going in.

Thanks for your time.

Have your mechanic do a thorough check of the entire brake system. My guess is that he will find discolored brake rotors, indicating overheated brakes.

If he does find discolored brake rotors, the cause would likely be either defective brake calipers, or possibly brake hydraulic lines that are deteriorating on the inside, and closing off the return flow of brake fluid to the master cylinder. Either of these scenarios will cause strange, random application of the brakes on one or more wheels, and that can produce phantom shuddering.

This is just a theory, of course, but the “burning rubber” smell could be from the brakes. Additionally, if the problem was engine-related, you would most likely have the Check Engine Light lit up (possibly flashing) when the problem takes place.

If it does turn out to be a brake problem, make sure that the brake hydraulic system is thoroughly flushed and new fluid installed, along with replacement of the rotors and calipers and/or flexible brake lines.

Alternatively, the problem could be the result of worn-out inner CV joints. First have the mechanic focus on the brake system, but if the brakes check out okay, the next thing to concentrate on would be the inner CV joints.