Re: Surging/shuddering between 40-60mph in 5.7l
Same problem on my 05 model. It was a second hand model with 65k Km, I have always noticed this problem, I hate this problem. Here in Italy there are almost no HEMIs so the technicians at the garage know nothing about this model. The chief technician at the garage was very surprised for this behaviour, he thought it was a misfire problem and suggested to change the injectors, however as the car has bifuel (LPG) and the problem is exactly the same with LPG, he tested the spark-plugs (changed recently), cleaned the throttle body, changed the EGR valve, however none of this attempts changed the behaviour.
I hate this, I believe a 50,000$ car shouldn't have this flaw, simply unacceptable, and I'm sure that this flaw is by design, as Daniele states.
BTW this flaw is enhanced by HEMIs suspension system, because I have noticed that when cruising on the highway any tiny imperfection on the road's surface makes the car vibrate in a very similar way; that is when the engine/transmission stutters, the whole car will "micro-vibrate".
Probably most of the owners won't feel this, but I'm highly obsessive and I suffer from this.