Engine surging

Tiny
DOWNRIVER
  • MEMBER
  • 2000 VOLVO S80
  • 2.9L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 101,000 MILES
This car will start to surge after it has warmed up. There are no issues with the car prior to warm up. The engine gently surges when cruising between 30 and 45 mph. There is no surge at highway speeds. The tachometer will show a constant acceleration and deceleration when cruising at these speeds.

Check engine light is on.3 codes: P0036, P0442, P0136
The airbag light is on and that happened when the guys recovered my seat and unplugged the airbag connection line.

An alarm system needs servicing occasionally shows up and the service light does the same.

I replaced the sparks plugs since this started happening but have done nothing else. All hoses appear to be in good shape and connected properly. I did notice that the plastic tubing that covers the wires in many places is beginning to disintegrate.

Other than the engine surging the engine runs very well and the gas mileage has not changed.
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Friday, November 18th, 2016 AT 4:20 PM

14 Replies

Tiny
JOHNNY G.JR
  • MEMBER
Does it surge when cruise control is on?
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Friday, November 18th, 2016 AT 5:04 PM
Tiny
DOWNRIVER
  • MEMBER
Have not tried cruise at these speeds. I will check that today. What if the answer is no?
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Saturday, November 19th, 2016 AT 3:11 AM
Tiny
DOWNRIVER
  • MEMBER
Drove the car today and everything was fine until it warmed up. The surges began a short time later. When I switched on the cruise control it behaved the same way. Surging about 500 rpm's and then backing down again.

I failed to mention in my initial post that when the surges begin, the throttle will have an area where the engine does not respond until it is almost on the floor.
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Sunday, November 20th, 2016 AT 9:44 AM
Tiny
KEN
  • ADMIN
Hey Downriver,

The first code is the secondary o2 sensor behind the catalytic converter is bad, I would start there, Also after you are done with that here are some services you can do to help the problem.

https://www.2carpros.com/articles/check-engine-light-clear-codes

and

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

and

https://www.2carpros.com/articles/mass-air-flow-service

Please let us know happens so it will help others.

Best, Ken
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Sunday, November 20th, 2016 AT 5:16 PM
Tiny
DOWNRIVER
  • MEMBER
Cleaned MAF sensor, checked for vacuum leaks and found none. My OBD sensor says there is one O2 sensor and it is operating but I know there are 4. I checked the sensor electrical lines and they appear to be good. Not sure if I should start replacing sensors. Car runs the same as it did before.
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Monday, December 5th, 2016 AT 7:23 AM
Tiny
KEN
  • ADMIN
Hey Downriver,

When was the last time you replaced the spark plugs? Check the air filter to make sure it is not plugged and check for cracks in the intake boot.

Plus sometime cleaning the MAF doesn't do the trick and it must be replaced.

Also we have a Volvo tech on our team I will see if he can help us out here. I sent him a message.

I will watch the thread to make sure we get the problem fixed.

Best, Ken
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Monday, December 5th, 2016 AT 11:16 AM
Tiny
DOWNRIVER
  • MEMBER
Thank. Just changed the plugs. 100k on the original ones. The air cleaner is fine and the intake boot also.
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Monday, December 5th, 2016 AT 12:26 PM
Tiny
JIS001
  • EXPERT
The o2 sensor fault looks like it is the one behinde the right side cat (passenger side) and PO442 is for your cat efficiency. Check the CAT to see if is plugged up or broken.
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Monday, December 5th, 2016 AT 1:11 PM
Tiny
JIS001
  • EXPERT
Also forgot to ask. Do you have a turbo charger on these?
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Monday, December 5th, 2016 AT 1:44 PM
Tiny
KEN
  • ADMIN
There is my Volvo tech! We rock.
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Monday, December 5th, 2016 AT 3:45 PM
Tiny
DOWNRIVER
  • MEMBER
This is a 2.9l non turbo
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Monday, December 5th, 2016 AT 5:58 PM
Tiny
JIS001
  • EXPERT
Ok thanks. Then have the catalytic converter checked to see if it broke inside.
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Monday, December 5th, 2016 AT 6:33 PM
Tiny
DOWNRIVER
  • MEMBER
I haven't had the cat checked yet but the problem has changed a little. The surging is only at very low speeds now. About 15 mph. I rarely drive this slow so I have little motivation to take this in. The Volvo dealer is not close and they usually want to do more repairs than the blue book value of the car. The throttle position problem still happens occasionally and I wonder if should go ahead and replace the sensor or do you think this all relates back to the cat?
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Tuesday, December 20th, 2016 AT 2:07 AM
Tiny
KEN
  • ADMIN
This sounds like a sensor problem, it might be time to replace it.

Please let us know happens so it will help others.

Best, Ken
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Tuesday, December 20th, 2016 AT 10:18 AM

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