I have a 07 Impala (3.5 liter) with an engine knock at 1000 to 1500 rpm. It has been in the Dealer shop 3 times with no resolution. I have been advised to drive intil the noise gets worse! Any other notations or complaints. The car has 2200 miles? Dealer thinks it might be coming from the exhaust manifold??

Hello, This car is too new to be having these kinds of problems. I would check into Lemon Laws in Nebraska and hope that you find some help. This site may provide additional information: http://www.mycarstats.com/safetystation.asp?mmmakes=CHEVROLET&mmmodels=IMPALA&year=2007%20&ComponentTab=RECALLS I'm very sorry to hear about your car! That just stinks! CarGrrl

If it is a deep sounding knock I would be inclined to think main bearings. If you drive it till it gets worse the engine will be trash and I think the dealer knows this. The exhaust manifold has nothing in to knock but may be a route for the sound to come through. An actual knock is made by parts hitting each other that shouldn't. I would take it to another mechanic who doesn't have anything to lose (like the dealer) by telling you what is actually going on. I think they owe you another car or at least a new engine.

I concur with CarGrrl and Corollanut. Another possability could be timing sensors are miscalabrated causing engine detonation or pre-ignition, but that is usually heard when starting off from a dead stop, or speeding up. I would start my own file and get copies of any work/visit that has been done.

dud chang da enge of ue car

If the later impalas were anything like the '02s I ran into when I worked in a dealership service department, it could be a loose accessory bolt. GM was notorious for underfilling the coolant (causing heater core failure) and leaving alternator bolts loose.. from the factory.