99 S80 runs a little rought with "drive slowly service urgent" on dash
 

Hi everyone,

I have a 99 S80 which seems a little sluggish but the engine is fairly smooth. When it has been sitting for a couple days though it runs very rough until it warms up. The check engine light flashes and a message of "drive slowly service urgent" appears on the dash. Checked the plugs which look worn but not fouled. Also when the car is turned off there is a tiny "puff" sound which I think is a little backfire. After it warms up it smooths out but warning lights are still on and car isn't slow but certainly not quick either.

Any ideas on this? Don't know how I can check the codes so not sure what is going on. Also is there a plug that works best in this car? Current volvo plugs have 3 prongs. Have seen some bosch and ngk with 4 prongs while all others seem to have 1. Any help is appreciated.

You might have a bad coil pack.
Some auto zones will pull the codes.
I would use Volvo plugs.

thanks tech, as always I appreciate your advise. The autozones out here can't pull the codes because of a lawsuit by some mechanics union. Any other way of knowing which coil pack it might be? All the plugs have approximately the same wear.

Hard to tell without pulling the codes.