View Full Version : 2004 Deville rough idle

12-14-13, 10:48 PM
Since last month i noticed my car had a slight shake when i come to a stop. It only shakes for about 1 or 2 sec on and off.. or until i drive off. My check engine light has not came on. And i cleaned my throttle body with some throttle body cleaner, and it still shakes. It only does it when im stopped at a red light or sometimes when im in park. If anybody can help me with this problem i would greatly appreicate it.

12-15-13, 01:28 AM
How old are the plugs and wires, and what model and year are we working with?

12-15-13, 01:58 AM
'04 Deville Luke, thread title. You need some sleep ;)

How did you "clean" the TB? Rag, old tooth brush, both sides, perimeter and bore? Or just a spray and wipe of the front of it?

12-15-13, 10:04 AM
I bought the car with 65,000 miles on it and i had it for a little over a year now. So i really dont know how old the plugs and wires are.
I cleaned both sides of the TB with a tooth brush and rag. When I cleaned it, the rough idling stopped for about a week. I also noticed when it does shake the headlights dim while its shaking.

12-15-13, 10:33 AM
Your engine has no spark plug wires. It uses C-O-P (Coil On Plug) ignition.

You need to either find a real GM/Helm serfvice manual set (eBay or www.helminc.com) or subscribe the car to a multi-year access to www.alldatadiy.com. The car and drivetrain are nothing like what you may be used to.

if the engine has a rough/low speed idle then the dimming lights occur as a product of low alternator output - the alternator/regulator put out only marginal voltage and amperage at healthy idle; anything less (in rpm) and the electrical system "starves", and if the battery is not at 100% that worsens the problem. Battery age ???

12-15-13, 10:46 AM

What is your voltage, both static and at idle?

12-15-13, 12:51 PM
When I brought the car they told me the battery has been in there for two years, so with tht being said the battery is problem 3 yrs old. I put woofers in the car about a yr ago. So tht could be the problem with the voltage I never thought about tht. Im about to go check the voltage right now. I really appreicate u guys trying to help me with my problem.

12-15-13, 01:51 PM
I just checked the voltage on my battery it wasnt constant it was jumping before 12.05 and 10.84 that was while the car was off, and i checked it while the car was idling and it jumped to 14.84 and stayed constant at 14. And i noticed it was a funny odor coming got the tailpipe.

12-15-13, 02:09 PM
14's while running is normal, but those static readings are low.

12-15-13, 06:36 PM
So i need to get it charged.

12-15-13, 10:24 PM
Your alternator is charging it, or at least trying to. If it is THAT weak, it may need to be replaced, but I'd get it tested first.

12-15-13, 10:35 PM
It could be a vacuum leak somewhere. Get a can of carb cleaner and spray around any vacuum hose, around the throttle body gaskets and rubber spacer between the intake, along the base of the intake, and the injectors while engine is running. Low battery voltage could be a potential problem as mentioned earlier.

12-15-13, 10:54 PM
@ranger and v-swagon. Ima try both of those tomorrow. Ima keep u guys posted. And let u if it still a problem. One again I surely appreicate all the feedback.

12-16-13, 04:16 PM
Welcome , If your battery was not at 10 volts because of power being pulled while testing (eg door open ,trunk glove boe etc.) it's going to be cheaper to buy a battery now than run the Alt until it works its self to death. Did you hook your new sound assys (like an amp or something needing a power source) to a keyed on connection or always on connection? just asking. You can go to a parts house and put a battery load tool on the battery and check its value...you don't have to buy it there just check it, drive across the street at another place and have it checked there also.. then buy one where you want. also make sure the trunk and engine compartment light turns off when closed...I find that turning off assys before my car prevents 'top of the battery' drainage at start-up, (heater, fan, radio, 12v chargers, wipers, get in and shut the door, even your foot on the brake can have an effect.. The DIC should show charging at start-up to be at least 12 volts. if you can leave the drivers window down tonight ,all assy off, in the morning reach in an turn key to 'run' and quickly push DIC button to battery and check volts.... N*'s rock. Ed

12-16-13, 11:08 PM
Ok ima try that. I took my battery to autozone and got it charged and checked they told me the battery was bad. But i had my system connected to a keyed on connection