07LS

When warmed up I can feel the engine not running smooth while in drive and idle. When in park, it's less noticeable. Slight vibration can be felt through the vehicle. Feels like misfire. I have been feeling this from the day I bought it. When I look under hood while it is running I can see the engine shaking. The salesman said "it's a big engine it is normal". I owned vehicles with "big" engines before and they ran smooth. My question is do I need to put on more miles on it because it just needs time to break in or is this possible problem that I should have service dept check? it has1200 miles now.
5.3L, not the flex fuel version. Manufactured Jan/06. I tried to find some info in older posts, but couldn't find anything. Thanks for any suggestions

Clay24

know you said it is not flex fuel but i would look into where you get your fuel i have had this problem before not in my 07 but i came to find out that the place i got my fuel didnt have a clean record had to change the filters injectors etc

07LS

Thanks for response. The engine runs rough regardless of where I get gas. I do not go to same gas station. Typicaly I use Arco that I am using in my 02 Dodge Ram and never had problems. Occasionaly I may get Shell or 76. But hardly ever in same location. But I do know what dirty fuel can do.

tj

I notice a shake as well. I'm going to try a botttle or two of Techron to see if it's gunk in the injectors.

DarkOne

+1 on the Techron, it should help cleaning the injectors. You can also try to put the Super Unleaded in your tank once. I use the Plus. Where do you live? If its cold then let the engine warm up a bit. I have had the same problem in my other truck, put some Techron in the system and no more. I probably used two bottles to make it more concentrated.

engine2

I notice a very very light vibration/rough idle on my 07 non flex fuel while sitting still and in park. At first I thought it was the base from from my stereo, but noticed the same occasional vibration when I turned the radio off. I am not too concerned about it yet, but I will have it checked out at my next oil change or service.

engine2

Sales people will tell you anything to get that unit off the lot. I was amazed how many sales people (I went to several dealerships before making my purchase) knew less about their product that I did (I am no expert by any means).

The good thing is that if it is something serious it should be covered under warranty. Keep us posted.

07LS

Thanks for all responses. I live is S. California so no problem with cold. Yes it is freezing now 55F but that is just being spoiled.
With 1200 miles I would not think that there is too much buildup in the injector even if the fuel I am getting was not the best quality.
I will try to fill it up with Super and see if it makes any difference. Normaly I use regular 87 octane as they recommend.

doo600

There is no buildup on the injectors in 1200 miles. If it's running rough you need to get it in to a dealer for a diagnosis before you do some serious engine damage.

07LS

Do you think it could be more serious problem? I also noticed that the end of the exhaust tailpipe is very black and coated with ash kind of material.
Also my gas mileage is far different from the estimated so I don't know if all this has anything to do with the rough idle or not.
I called one dealer and they told me: If your check engine light is not on, don't be concerned.