I bought my 2008 Crossfire (Automatic) from the Chrysler dealership just over a year ago. When I bought it, the car had about 6k miles on it, and it now has just over 19k.

I have gotten 3 oil changes at the dealership (one shortly after getting it, one around 14k, and finally at just under 19k). The first two times they used Pennzoil 5w40 and said that is now what the recommend instead of the M1 0w40 (really it has to do with their contracts, but it meets the specifications in the manual).

Since my last oil change about 2 months ago, I have only driven it about 900 miles, and have noticed a few problems.

1) it is making a fast ticking sound constantly (gets quicker and louder when I accelerate)
2) it is making a slow thumping sound when I am at a constant speed (40-80 mph and in addition to the other)
3) there is a bit of a lag between the petal and acceleration and it isn't accelerating as fast as it had been.

So far, all the maintenance has been done at the dealership. I took it to a local mechanic that my family has been dealing with for forever to get the back tires changed (he was much cheaper), I thought it might be the spark plugs and asked him to take a look at it. He said they were in great condition, but pointed out that the dealer used the wrong oil this last time. Sure enough, the sticker says 5w20 (the same oil they put in my wife's 2012 Kia Optima!).

So here is my question, can the oil be causing those issues? What kind of damage can the wrong oil cause? What else could be causing that?

Thanks for your help!