: 2002 caddy deville

07-01-09, 10:00 AM
i have a 2002 cadillac deville and for a while now i have been having a bad rough idle and the acceleration is less than perfect.... short and sweet my question is that what is the economical way to test the issue accurately and a good online store to buy the coil packs if needed... Thanks

07-01-09, 11:03 AM
Before you buy anything do a search for plenum and check that. While you're there, clean the TB.

Mark C
07-01-09, 02:42 PM
If you had a bad coil pack chances are you would have an SES light on and a P0300 misfire code in your current DTCs. Pull your DTCs to find out what the car thinks is the issue. P0300 by itself, probably a coil pack, or plugs or plug boots, P0171 or 0174 with or without a P0300 means vacuum leak and probably a split plenum boot.