Rattling when on idle!!!

[Ramin007]

It doesn't make sense to me that engine naturally runs rough on idle mode. It is definitely the low 500 rpm. When it is higher, like when the car heating up in park mode, the roughness is almost gone... 500 rpm is too low.

 

[Greeco]

It doesn't make sense to me that engine naturally runs rough on idle mode. It is definitely the low 500 rpm. When it is higher, like when the car heating up in park mode, the roughness is almost gone... 500 rpm is too low.

I agree! When I'm stopped at a stoplight my engine vibrates at 500 RPM. If I hold the brake with my left foot and slowly apply pressure to the gas peddle it only takes about a 200 rpm increase and the vibration goes away. The vibration is clearly tied to the low idle RPM but the dealership can't/won't do anything about it. Frustrating!

 

[Warriorpluto]

I agree! When I'm stopped at a stoplight my engine vibrates at 500 RPM. If I hold the brake with my left foot and slowly apply pressure to the gas peddle it only takes about a 200 rpm increase and the vibration goes away. The vibration is clearly tied to the low idle RPM but the dealership can't/won't do anything about it. Frustrating!

Well that's just how they are. I have an envoy Denali with 5.3 and it's always had rough idle. No matter the octane. Bought the truck with 112k miles and now have 198k. Still running strong and whooping ass on the streets with my homemade tune

 

[Danny3737]

Run a tankful of Royal Purple fuel ejector cleaner and see if that helps. It did make a difference in mine. You can get it at most parts stores and Walmart.