QUESTION: Hey I'm interested in a 2006 dts the first year they started that body style for it and I had a question about the idle. I heard it ran yesterday and I must say that it has an extreme misfire. It has a harder start, have to put foot on gas sometimes to crank it and the idle is like its running on like 4 cylinders, it goes up, then decreases gradually and then goes back up but it's running rough and it's putting in the process, I was told that it could be either the coils, the plugs, or ignition, I also took a video of it running also, just wanted another opinion on what it could be, thanks a lot
The body style premiered with the European look in 2000.
As for drivability, video or not, it does no good for anyone to guess and the answers your were given are correct. It can be any of those things including a bad injector, problem in the computer system.
Don't go to a dealer. You will be writing me and telling me as to how you paid $1,000.00 and the engine still has problems.
Find a reputable service center in your area. They will know instantly if it is a spark plug problem by removing them, a bad coil, imjector, computer with a diagnostic scanner.
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QUESTION: Ok I appreciate the info, and also I wanted to know what would cause that stuff to become faulty?
Just driving the vehicle can cause anything in the engine or electronic system to fail. If the engine is started and not driven to a warmed up condition, the spark plugs can fail over time. It is common for people to be excited having a low mileage vehicle that was exposed only to city driving. Those are the worst cars to have! Highway miles are much better.
Without even knowing what is wrong with the vehicle, I cannot tell you why some component failed. Even new components can have issues. In your case, there are many possibilities that can be the engine running problem.
My suburban started running very bad at 180,000 miles. Well, it was later found the spark plugs had 180,000 miles on them, 80,000 miles past their life! The distributor bushings were just plain worn out from mileage!
My other Suburban, would drive fine except for an occasional miss. Then one day it was running on 7 cylinders all the time. I removed the plugs and found the cylinder that was not firing. I replaced the plugs, cap, rotor and wires. It runs perfectly now. A spark plug had internally failed.
By the way, you may see sometimes a selling feature is that the vehicle is mechanic owned. Another way to put this is "Don't buy me, I have never seen maintenance." LOL When the tech works on vehicles for a living, he sure does not work on a vehicle that actually costs him time and money. I know, I am one of these guys! lol Why fix something not broke?
There is no rhyme or reason as to why components fail. In electronics, vibration from normal use can break circuit boards internally. Heat can cause electronic to fail. When I was a kid a long long time before computers, I was junking cars for my dad with 60,000-70,000 miles. Now vehicles can go 300,000 miles plus, which is really amazing because of the electronics that can fail. Of course engines now run much more efficient and computers offer a controlled environment.
Back when vehicles were simpler and one could rebuild his own carb, alternator, starter and not rely on parts houses that supply highly questionable rebuilt products, life was easier. Now, the tech is only as good as the components he replaces. I have had spark plugs junk new in the box! Junk "new" alternators etc. That is why I don't ever assume I can't have a problem at any given time.
I remember in 1992 I bought a new Dodge Dakota. Within 1,000 miles I had to have 4 transmissions replaced. In 1996 I bought a new Doge Ram. The first thousand miles there were 5 transmissions replaced! Of course, I never bought a new Dodge truck since!
The one very crucial thing you may not know. The engine in your DTS when running good is a very high performance engine with power and mileage. The bad part is to make this happen, Cadillac has employed aluminum engines because of weight since 1982. They are great engines, but few understand the aluminum engine's worst enemy that will destroy it quickly is heat. If the hot light comes on, it does not matter where you are, the engine needs to be shut down now! If not, the engine literally begins to melt! Many of the cars in the junkyard have been overheated and the engines are junk, leaving only one option if more damage done is blown head gaskets--a $5,000.00 crate engine from GM. I give you this warning up front because I deal with this on this site quite often.
Instead of guessing why a component has failed in the engine, you first have to have the engine diagnosed as to the exact problem before wondering what caused whatever problem you have.