Hi All,
Great Forum, its helped on many issues! So yesterday I was washing and waxing my 99 S-80 T6 95k miles and when I took off the front bra I noticed that the motor was simply dirty due to the FUN winters we have in Idaho. So I very gently cleaned the motor and lightly sprayed the soap off, things I have done to my Chevy Truck many times. I drove the car later that day and no problems, but when I was going to town today I was letting it warm up and I noticed a strange smell from the exhaust and saw I now have the emission system service required light on. The Idle is now running rough, feels like it is missing on a cylinder or something. It will only rev to 4k and its normal acceleration is gone. I pulled all the electrical plugs I could and they were dry, not sure if this is a fluke or related. Any help would be GREAT. Thanks

 

Check your connection at the mass air flow. You say you washed it maybe you got it contaminated with water. I would start there.

 

Checked the MAF connectors, everything seems to be fine. I let the car sit for a few days and it still runs the same (rough idle, power is gone) I am just wondering if there is some type of safe mode the volvo computer shuts the car down to when it detects something amiss. If such a thing does exist, how does one clear the code and can a local shop do such a thing? My closest Volvo dealer is 350 miles away. Any help would be great!

 

Sounds like a bad coil pack and/or spark plugs. Does the miss seem to smooth out a bit as the RPM's climb? The smell is the unburned fuel hitting the converter in the exhust, and the emission system service required light is from the O2 sensor getting a strange reading from the rich exhaust gases. I've had to replace 2 coilsso far on my 99T6.