Question about Ecotech (09-10)

I was wondering for those with experience with the Ecotech if they can answer a few questions I have since I don't really have experience with this vehicle yet.

Is engine tick during normal operation something that these engines do? My tired 3100 did this, which was normal for the mileage that it had but mostly went away after the engine warmed. Mine has been doing this without changing volume after warming up for some time now.

Also how much have you observed your mileage change since the start of winter? I know due to idling and other factors in winter (like timing changes to prevent knock) that mileage normally decreases, but I have been noticing a decline in my mileage up to 10mpg less than what I was getting in the summer (imperial; from 35mpg to 25mpg all city pretty much) which seems rather large to me.

Also my heater when it comes on make an loud noise in the cabin, a very rapid knocking sound.

Basically what I would like to know is if these things are normal for this vehicle or if I should be concerned and get them looked at. I have never dealt with these cars nor 4 cylinders in general for that matter, only V6s and V8s.

the knocking sound seems like the flap for fresh air to heat OR the vent it comes out.. i get that once in a while.

I dont have a tick, but its valve train sounds worse in winter.. more sewing machine like (although i just put synthetic in for the first time ever, back dino next time)

my mileage went down, i think i got 25-28 highway (at 85-90mph). in summer i usually get 30-32 with the same style and summer tires.

I actually got the knocking noise looked at when it got worse a couple days ago, turns out the blower motor fan blades were bent from the factory. Free replacement later and its super quiet and my car doesn't sounds like its going to explode.

Otherwise everything it working good.

10% fuel economy drop in winter is considered normal caused by winter blend of gas and our computers controlling fuel mixture until a car is warmed up.you say mostly city driving so your car never warms upto optimum running temp(20 mins) i think the 1.6 is a bit noisy(sewing machine like)but there are much noisier engines ie nissan versa 1.4l (has timing chain) extremely ticky noisy like