Surging - Pulsing on Acceleration

Post by **IdahoBob** » 19 Feb 2019, 12:48

2002 XC70, 192,000 miles
When accelerating the car has a rythmic pulsing or surging.
When I'm a steady speed or decelerating: no pulsing.

Any ideas on what to check?

Thanks Again!

Post by **abscate** » 19 Feb 2019, 16:05

Boost hoses

Weak Turbo control valve , hard to diagnose

dlundblad · Post by **dlundblad** » 20 Feb 2019, 01:47

Could also be a failing CV joint depending on the severity.

Post by **IdahoBob** » 10 Mar 2019, 21:30

Update:
> Checked CV joints in front axle. One of them actually came apart when I pulled on it. So, I installed (what I think is) a decent used one I had in the garage.
> Complicating the story: I also have a scraping sound coming from somewhere behind the driver's seat. It could be in the rear axle or maybe? I pulled both rear brake rotors, verified that the handbrake shoes were intact and that the brake calipers were functioning properly.
> Today, after installing the (maybe good, used) axle and verifying the brake function looks correct, I have:
* The vibration (a pulsing, hopping) is still there, possibly worse
* I still have the scraping sound. When accelerating it stops or diminishes, then when I just cruise or decelerate the scraping can
be heard.
Any thoughts?
What does the car do when the CV joints in the driveline are going kaputt? Scraping and hopping maybe?
How do I know (what do I hear, feel, smell, etc.) when the rear differential is collapsing?

Back story: 192,000 miles. Has been driven the last 45,000 by someone who's on and off the gas & brake pretty assertively; thus any CV joints would have had a lot of hammering.