An ignition coil may fail causing one of the cylinders to misfire. Each of the two banks of cylinders has its own coil assembly. If one ignition coil fails the coil assembly for the corresponding cylinder bank must be replaced.
Car Problem Reports
Cadillac DeVille DTS Misfire Due to Failed Ignition Coil
Cadillac DeVille DTS Problem
Average Mileage: 106,274 mi (82,347 mi - 140,000 mi)
Visitor, 2003 Cadillac DeVille DTS, 90,000 mi
Car idles rough and check engine light is on and sometimes flashes. Worse when engine warms up but idles rough even when cold. Diagnostic check shows P0300 and 303 codes which indicates a misfiring in the #3 cylinder. I haven't troubleshot it any further. I don't want to drive it as it could do damage to the catylitic converter when the check engine light flashes.
Visitor, 2004 Cadillac DeVille DTS, 130,352 mi
My vehicle was doing fine. I started it up one morning, and the check egine light came on,along with misfire and vibration. the diagnosis is misfire in # 4 cylinder. I am parking it until it can be repaired.
Visitor, 2002 Cadillac DeVille DTS, 82,347 mi
misfire on one clyder
Visitor, 2003 Cadillac DeVille DTS, 105,000 mi
I'm having that same issue now, i was told by a mechanic that's it's the 6th cylinder that's having the issue.. My question is, is this bank of coils in a reasonable spot to work on.. I've fixed my door actuator n Chg oil, etc, but I'm kinda nervous bout messing the Northstar, any help would b greatly appreciated.. If it's not to difficult, I'd like to try rather than pay 620 to get it fixed
Visitor, 2004 Cadillac DeVille DTS, 106,000 mi
replaced the ignition coil with a new one from amazon.com. Cheapest prices around.
Visitor, 2003 Cadillac DeVille DTS, 98,000 mi
Replaced front and back coil and plugs
Visitor, 2004 Cadillac DeVille DTS, 98,500 mi
Problem started around 98000 mi. Green Chevy/Cadillac diagnosed and repaired the problem quickly