My 2002 S60 has been sputtering off and on for about five weeks. I put in some higher octane fuel and it improved for a little while. Today was worse than ever. The check engine light came on and the error message "try slow down or shift up" came up on the dashboard. In the past it would sputter for about 10 minutes and then go away. Today it lasted for an hour. Any ideas? Thanks!

 

Have the codes pulled first. Then we can try to help you.

 

Can I pull the codes myself? Don't know how...

 

You need a scanner try Auto Zone.

 

have you tried another gas station? My other car doesnt run as too well with a certain "brand" of gas... so i actually need to travel a few miles further to get to the 'better' gas station.

... but like tech said: get the code. Nothing bad's gonna come out of that....

 

I tried better gas and it appeared to work for a little while but it's back again. This time worse than before. Here is what I'm getting now...

Check engine light - code P0303 = misfire in cylinder #3
Error light occasionaly on the dash that reads "try slow down or shift to higher gear.

Any ideas?

 

Most likely a bad spark plug or Coil.

 

Is the coil just the wire that plugs into the spark plug? Can I get that at Auto Zone? Thanks!

 

Your car has a coil that slides onto the spark plug.

 

This is what the coil looks like;



I found that the dealer is the only one who carries them. I may be wrong. Someone else may be able to let you know where to get them.

 

http://www2.swedishpartswholesale.co...+Coil&dp=false
You can buy one here.

 

you can also get them at www.ipdusa.com

 

http://www.eeuroparts.com/Main/PartD...px?id=30713416 + Free Shipping

When is it Recommended to change the coils?

 

Not really a specific time. Regular inspection for cracks will tell you when it is time to replace them.
If they are cracking I would replace them.