Rought Starting

[richardson42]

I have a 06 perf and when you start it up, it sounds like it idling very rough for about 10-15 seconds and then it goes away and runs very quietly. Has anyone else noticed this or know what would cause it?

[Southern]

There are so many things that could cause this.......... Does the Ck Engine lite come on?
How many miles?
Maybe a bad spark plug.......
Some things that happen.....Older Caddys had a problem with Cracked plenums............ or any kind of leak around hoses etc.......

[richardson42]

no check engine light..
car has 44000 miles
all maintenance has been done
no leaks that i can see

[Superjim]

Mine makes a little noise when I first start it for the first time after it has been setting over night.
The noise lasts for about 10 or 15 seconds...but it is not running rough...it is running smooth.
I only notice it if I do a remote start as I come into the garage.
If you are in the car...you don't hear it.
My 2006 Performance has almost 70,000 on it.

Texas Jim

[z06bigbird]

I noticed "loud tappets" on my 04 with 24k miles on it. Dealer reprogrammed the dumaflagie, and it cured the problem. Service mgr knew exactly what needed to be done. Under warranty too. (about 2 years ago.) 3.6 engine.

[Tomko]

Could be poor quality gas.

Are you using Top Tier Gasoline?

[Superjim]

Originally Posted by richardson42

I have a 06 perf and when you start it up, it sounds like it idling very rough for about 10-15 seconds and then it goes away and runs very quietly. Has anyone else noticed this or know what would cause it?

I would respectfully, like to ask for a little clarification here...

When you say it "SOUNDS" like it is idling rough...do you mean you hear noise for a few seconds and then the noise goes away...
or do you mean it is missing and you can actually "FEEL" it running rough.

This is two entirely different problems.

Texas Jim

[richardson42]

Jim,

It seems that my car does the same thing as yours since I really notice it when I do the remote start. However, you can feel it a little when inside the car. In response to the other post I only use super gasoline from either shell or bp. thanks for the help.

[CaddiLukKing]

My 07 PERF. Sedan Does the same thing! when Starting it sorta feels like it Jitters and Viabrates at 1200 RPM's but after 10 15 seconds when RPMs go down to 800 it stops and everything sounds smooth. My 01 deville had done the same thing... i have always Used Only Premium gas on both cars.

[DevilleDeeman]

I get the same thing on my '06 DTS, dealer told me it's normal. Just sounds a little noisy and rough for 10 seconds than smooths right out. I know its normal because my friend has a '07 that does the exact same thing.

[rjm]

Same here. More pronounced if my car sits for a few days. Dealer told me its due to ethanol in the gas, and to find a gas station selling 100% gasoline. But I've found that to be extremely difficult what with the gov't now requiring E10 and considering a bump to E15, which the techs tell me would be disastrous since most engines are designed to run on 100% gas, and at this time its not known how much detrimental effect E10 will have on them, but they're certain it will shorten engine life.

[DevilleDeeman]

Originally Posted by rjm

Same here. More pronounced if my car sits for a few days. Dealer told me its due to ethanol in the gas, and to find a gas station selling 100% gasoline. But I've found that to be extremely difficult what with the gov't now requiring E10 and considering a bump to E15, which the techs tell me would be disastrous since most engines are designed to run on 100% gas, and at this time its not known how much detrimental effect E10 will have on them, but they're certain it will shorten engine life.

E10(10%) isn't bad for an engine, its an ethanol blend which cleans the engine as it drives. If your worried about it I would just bump up to 89/90 octane at the pumps, seems to make my car a bit smoother. I never put regular grade gas in my Cadi's even though the manual says it's fine.

[richardson42]

Update...now my check engine light is on. I took it in and the dealer said it probably needs an "upper engine clean" since an O2 sensor code came up. Can't wait to see what they charge for that. I also tried the 100% gas as previously mentioned, hope that had nothing to do with it.

[Superjim]

Originally Posted by richardson42

Update...now my check engine light is on. I took it in and the dealer said it probably needs an "upper engine clean" since an O2 sensor code came up. Can't wait to see what they charge for that. I also tried the 100% gas as previously mentioned, hope that had nothing to do with it.

The o2 sensor will be covered under the warranty.
Unless it was bad gas, the 100% gas had nothing to do with the o2 code.

I run 100% gas (Premium only) any time I can find it.
My particular car runs better on REAL gas than on the ethanol crap.

Let me preface the below comments, by saying, I have never had an "UPPER ENGINE CLEANING" in over 50 years of driving nor did I ever think I needed one.
I may have needed it and just didn't know it.

Just me personally, but I would be a little leery of "UPPER ENGINE CLEANING".
Just my humble opinion, but I have always thought that "SERVICES" like that are just another way of transferring the money from my wallet to theirs without me seeing any tangible benefit.

But I "WILL" readily admit... cars that are driven slowly around town all time and never (or very, very seldom) get treated to good bursts of wide open throttle, may need services that my car does not need.

Texas Jim