Rough Idle, Check Engine Light Illuminated

talbotpj · Post by **talbotpj** » 30 Oct 2010, 12:49

Hi,

Drove my '98 S70 on a 400 mile trip yesterday and all went smoothly. After arriving at my destination, I grabbed some lunch then got back in the car 20 minutes later and was greeted by rough idling (between 500-1100 RPM) and a check engine light. The car still drives fine, but something is obviously wrong with it. I want to think it is just worn spark plugs, but I am not sure and have none of my tools with me to check. Any ideas? I have to drive another 400 miles Monday morning and would like to fix the problem beforehand.

1998 Volvo S70, 5 spd, 136k

Thanks,

Pat

Post by **JRL** » 30 Oct 2010, 13:01

You have a CEL, read the code, please.
We can help but not blindly, you need to get that code read and post it
Sounds like you probably have a misfire code

talbotpj · Post by **talbotpj** » 13 Nov 2010, 12:47

Update: I finally read the codes and determined it is missing on ALL cylinders. Six codes in total, the 5 misfire codes and the "multiple misfires" code. I recently replaced the plugs, no help.

Why would all 5 cylinders suddenly start misfiring? Any ideas?

Post by **RobTheModd** » 13 Nov 2010, 13:29

what plugs did you install???

Usually you just need to do a stage 0...

Plugs and wires.

Post by **jblackburn** » 13 Nov 2010, 14:50

Could be several reasons, but start by making sure your plugs are new and gapped correctly -.028"

Run the car with the hood up tonight and look for blue sparks around the area of the ignition coil (it is on top of the drivers side wheel)

talbotpj · Post by **talbotpj** » 14 Nov 2010, 09:21

The plugs were installed after the problems started and yes, they were gapped correctly.

The thing that confuses me is the fact that all 5 cylinders started misfiring at once. Would just one plug wire going bad cause the misfiring of all cylinders? Or would it be a component that affects all cylinders such as the distributor or coil.

The problems are only noticeable at idle, and more so when the engine is cold. It seems to rev up to 2000ish rpm's when cold and stay there for a few minutes.

eatcubensis · Post by **eatcubensis** » 09 Dec 2010, 11:23

I am trying to resolve a similar situation. However, I feel the reason you have all of these codes is because you never cleared the codes to begin with. You need to clear all of the codes and then run your and see what codes come back up. Hope this helps.

Post by **jblackburn** » 09 Dec 2010, 11:34

https://www.matthewsvolvosite.com/forums ... =1&t=34542