Engine suddenly starts running rough

[pauldunlop22]

Today, out on highway for 45 minutes then driving 20 minutes city streets. Came up to a light and felt a sudden change in engine idle. From this point car ran very roughly engine light came on. Could hardly get car over 30 mph. Brake light check came on also. The car did not come close to stalling though. It ran as if I was in too high a gear. I switched to manual shift but did no good. Car shuddered all the way home. Anyone got any suggestions. The only other time I had a similar experience was when my alternator failed. Thanks for any help.

[JRL]

Your model year and mileage surely would help here

[pauldunlop22]

Forgot to mention that my XC is an 02 with 81,000 mi.

[stupidloose]

Had the same problem a couple of times before. All three times it ended up being an ignition coil. I finally went and replaced the other two just to get them done. If you don't have any diagnostic tools, Get a new coil (Which I carry for a spare in all my Volvo's) and just start swapping it from one cylinder to the other until it runs and takes the throttle. This is just one of the easier and cheaper things you can do at home pretty quickly. This is what I have found in my past experience with these symptoms. JRL will probably come back with some even better advice.

[JRL]

You need to have the CEL codes read.
Not only will that actually tell you the actual misfiring cylinder (if that's the case) but where to look in general.
You don't hunt and peck around, GET THE CODES READ

[stupidloose]

I was just giving you that option in case it wasn't even running enough to get it to a shop. Definetely get it scanned if its able to be driven there.

[pauldunlop22]

Thanks guys I will get the codes read and that will show the origin. I have had coil problems in the past and have replaced half the coils. We will see. I will keep you posted.

[pauldunlop22]

I took my car in code is for #3 coil. Got it replaced and good to go. Thanks your support!