SureTrack Community Fix: Shaky Pedals

Real Fixes from Mitchell 1’s SureTrack® expert information resource are documented issues from actual shop repair orders and community discussions. Read on to see how SureTrack can help you correct issues that are not easily diagnosed using OEM information alone. SureTrack is available at no additional cost in our ProDemand product.


Most complaints of vibrations through a vehicle’s pedals are related to the brake pedal. A vibration in the gas pedal is fairly unusual. SureTrack community member bmaples had a Chevrolet Silverado in the shop where the owner complained that the gas pedal vibrated when accelerating from a stop. They posed the question to the community, and with the help of fellow community member ericsautomotive and others, they were able to resolve the issue quickly.

The following Community Fix summarizes the interaction between members of the community that led to the solution.

Vehicle
2004 Chevrolet Silverado 1500 5.3L

Title
Vibration in gas pedal while accelerating, replaced brake booster.

Complaint
Customer complains that gas pedal intermittently vibrates while accelerating. Confirmed concern but noticed that it is only under half throttle or more when accelerating from a stop. Fast vibration that you can feel in both pedals and it can be heard.

Diagnostic Steps Performed/Parts Replaced
Checked vacuum and drove with vacuum gauge connected in-line with vacuum supply. Vacuum drops sharply and needle violently shakes between 10 inches to 0 inches of vacuum. At idle it’s 20 inches under harder acceleration, it does the same shaking but between 5 inches & 0 inches. Have determined it is the vacuum assist motor coming on. Check valve is working. I’m thinking there is a small leak in booster diaphragm or seal between assist motor and booster.

Best Answer from Community Member ericsautomotive
Try completely unhooking booster to make the issue go away.

Cause
Disconnected brake booster and issue went away proving faulty booster is the cause.

Correction
Replaced brake booster assembly, road tested vehicle and vibration has been eliminated.


SureTrack® adds to the power of ProDemand® with an exclusive combination of real-world knowledge and powerful diagnostic tools, all wrapped in an interactive community of professional technicians. Designed to help automotive shops increase accuracy and efficiency from diagnosis to completed repair, the industry’s most comprehensive repair information resource is just a few clicks away.

Want more? Here’s how you can see more Real Fixes in SureTrack:

About the Author

Nick Taylor

Nick Taylor is the SureTrack Community Administrator and a Senior Applications Specialist at Mitchell 1 with over 25 years of experience with electronic repair data systems. Nick previously worked in the automotive dismantling and engine rebuilding industries.