View Full Version : Rough Running 97 DeVille

10-31-05, 01:56 PM
My DeVille started running rough this weekend. The motor started missing on mild acceleration and backfires sometimes. Tried WOT to clear it out but didn't help. Motor has 90K miles and has never given me a problem. Any ideas or am I at the mercy of the local dealer? (Est $500 for a tune up)

10-31-05, 02:03 PM
:welcome: to the forums!

This is a common problem and we're gonna get you straightened out!

Do a search and you will see lots of info about similar problems and tune-ups

First of all pull the DTC codes from the dash. This will tell you what exactly is wrong.

If you haven't done any tune-ups then its probably good time for it. Its real easy and you can do it yourself.

You will need to replace plugs and wires with a set of AC DELCO spark pugs and wires.
Oil and filter change
Air filter change
Coolant change (not flush) just drain and refiull system with new Dexcool and supplement tabs.
Thats it! You can change the fuel filter too but not required.

Most likely you will see a code p0300 for engine misfire detected. When this happned to me, a set of new plugs and wires cured it. The other time it happened turned out top be a defective ignition coil pack. Very easy to replace and cheap. (eg dealer charged me 350 to do it, I did it for 28$ and 5 minutes at the autozone parking lot)

10-31-05, 02:33 PM
Thanks for the suggestions. I think I can handle the tune up. This is my first Cadillac and is awesome to drive. I bought it for a 250 mile RT commute to work each day and put 30K miles on it in 4 months. Changed jobs and only put 100 a day on it now. Still average about 25 mpg at 75mph. Can't complain. This will be the first real maintenance I've had to put into the car since I bought it.

10-31-05, 03:30 PM
I would suggest www.gmpartsdirect.com for your genuine gm parts. You usually get things for about half the price of the dealer. An example, had a front wheel bearing going out in my '97 Deville, its a sealed bearing so you have to buy a complete front hub. Dealer quoted me $400, I got the gm part number and went to gmpartsdirect and bought the same hub for $180 plus shipping.

10-31-05, 04:18 PM

10-31-05, 04:41 PM
Let me guess. You recently had the fuel rail recall done, right? Many, myself included have had the exact same problem soon afterwards. It seems that moving old plug wires around tends to make them fail. Follow Powerglide and Bubbas advice and get a set of OEM wires and plugs. I got my wires from http://www.rockauto.com and had them in 2 days for about $112. Bought the plugs locally for $5 ea. Problem solved. This was also on a '97 Deville.

P.S. Do not let the wires rest against the blower motor or any closer than neccassary. That will take the blower motor out in short order. It may go anyway as they are known to be problematic. New ones have been redesigned but installation is a PITA.