I recently bought a used 2009 Dodge Caliber SXT. For the first ~3000 miles of use, I was mostly driving 80-90 miles per hour on the freeway on a road trip and everything was awesome. Toward the end of the trip, I got the oil changed at a valvoline in Fargo, ND where we stopped in on the way home (The check engine warning came on). The valvoline employee told me they spilled a little oil while filling it up, but he showed me and everything looked pretty clean. At that same stop, I put no-ethanol unleaded gas in the tank (Not sure if that's relevant, but I'm from WI where all the gas has 10% ethanol).

Not sure if either of those could have this side-effect, but since that stop, the car seems to have trouble accelerating at low RPMs. I noticed it at first while navigating out of Fargo. It seems like lightly pressing the gas does very little, then when I get to a certain point, the RPMs go up passed 2k. The car also seems to shake a bit when accelerating while below 2k RPMs. It seems to be worst if the RPM meter is decreasing, then I lightly try to accelerate.

Everything was fine driving at high speeds on the freeway, but now that I've returned from that trip and I have to commute in bumper-to-bumper every morning, I'm noticing this quite a bit when I have to accelerate slightly while my car is finishing decelerating close to a stop. Like I said, I didn't do much city driving in this car before taking it out on the road, so I'm not POSITIVE it wasn't like this before, but I started noticing it after that oil change.

Could something with the oil change or the type of gas cause this? I've read that Calibers are really weak on the acceleration. Maybe this is just normal behavior that I didn't notice before? Any other ideas?

 

Also, I should mention that it doesn't shake while idling. Only while actually accelerating at low RPMs.

 

Mine does the same thing. From a dead stop, the car accelerates normally however when you are in traffic or slowing down, for some reason the car doesn't like to down shift when it is supposed to.

The shake? Not quite sure what to make of that. With how you explain it, I think it is a tire. Could be something as simple as them not being inflated properly to one not being balanced properly. You will feel those at slower speeds.

That's my thoughts without seeing the car.

 

I would try a set of spark plugs first. They are supposed to be changed every 30K miles.

Some of the odd feelings while deceleration may be the fact that the Caliber shuts off the injectors when decelerating until it gets to almost idle speed to save fuel when in D. It doesn't do it when in L though.