While coasting downhill even on mild slopes the speed picks up very fast?

2015 CHRYSLER 200

80,000 MILES • 2.4L • 4 CYL • 2WD • AUTOMATIC

KSTOCK

MEMBER
3 POSTS
FOLLOW

A while back I had to replace my alternator. My father installed it as he's done many self-repairs before. However, ever since then I coast downhill even on mild slopes my speed picks up very fast. Noticeably faster than before the alternator replacement. I have to apply the brakes frequently to avoid speeding and tailgating other vehicles. What could be the cause of this, and can anything be done to remedy the issue? Thanks for your help.

Oct 30, 2023 at 1:43 AM

Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.

STRAILER

AUTOMOTIVE REPAIR CONTRIBUTOR
54,178 POSTS

I would run the codes to see if any are stored, please go over this guide:

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

I don't see any programming that needs to be done when replacing the alternator. Here are the instructions on how the job is done correctly so your dad could go over it to see if he missed anything. The only other thing I can think of if there are no codes is to service the throttle body. This guide can help, and I have included instructions for our car as well.

https://www.2carpros.com/articles/throttle-actuator-service

Check out the images (below). Please let us know what happens.

Images (Click to enlarge)

Oct 30, 2023 at 12:09 PM