slight rough idle '07 V8

[RoyBell]

Just picked this one and there's a slight rough idle compared to my other '07 that has twice the mileage. Nothing serious, but noticeable to me. This one only has 93K miles.

Does not throw codes and I just put OEM plugs in with no difference.

Seems to drive ok, with good power and throttle response....but it feels slightly slower than my 180K mile '07, which could be in my mind too.

MPG seems down approx .5-1mpg vs the higher mileage one (15.5 vs 16.6) but that could also be from the tires and I think I need an alignment on this one.

Any thoughts?

 

[philipalberti_]

It could be your MAF sensor. Try cleaning it with some spray from autozone. I had a rough idle, but it threw up a code, and that fixed it.

 

[81runner]

Check the MAF, the PCV, the throttle body. If you changed plugs, did you replace coils? If none of the basic simple stuff helps, you may need to plug in a reader for some live data. Might be a vacuum leak, a fuel flow problem, the list can get long

 

[RoyBell]

I'll start with cleaning the Maf. It's not as rough as a vacuum leak and probably not noticeable to most people even. It's also random. Will idle like a Camry, and then give a little shake to let you know there's an engine there.

 

[That_Titanium_4RNR]

I'll start with cleaning the Maf. It's not as rough as a vacuum leak and probably not noticeable to most people even. It's also random. Will idle like a Camry, and then give a little shake to let you know there's an engine there.

Mine idles rough sporadically too, I have noticed it more frequently with my AC on. I have new plugs which helped for awhile but I feel like the thing is back to how it used to be

 

[swampdodo]

Motor mount bad?

 

[81runner]

A bad motor mount would just make the engine shake all the time at idle, it wouldn't be sporadic.

If you had a sticking or leaking injector, you would get an intermittent rough idle, and not necessarily get a cel. Your fuel trims have to go over +-30% to draw a code. Same with a minor vacuum leak. The ecm will adjust as things wear to keep the engine running normally. So you could be showing signs of something wrong without actually getting a code. A code only mean the computer THINKS something is wrong. Again, if the MAF doesn't get you there, might be a good idea to get some live data, better than throwing parts at it blindly. Just my .02. Good luck!