I have a 2007 2WD with the 3.7L engine. Lately, it's developed what I'd describe as a slight "stumble" in the engine. It's not too noticeable, but it's definitely there. It feels like the engine is almost missing, or starved for fuel for a second. Something's out of balance. Doesn't seem to have the get up and go it once had, and the mileage has dropped a bit. I've replaced the spark plugs and air filter, cleaned the injectors, tried running premium gas, checked the driveshaft to make sure it's balanced, had the dealer flash the PCM and update the software, and the wheels and tires re-balanced, so far. The Dealer can't seem to find anything wrong. There was a recall on the torque converter and they replaced it. No check engine light, and it's not throwing any codes. I'm going to try new O2 sensors, and check the EGR valve. Anyone else having similar problems? Any solutions?

 

The 3.7 is a "stumbly" engine (lol) by design...I was concerned about a lumpy idle but apparently its normal.

An off chance, but I had an idler pulley bearing that was slowly seizing on me...was getting weird random o2 sensor codes and a greater than normal erratic idle...about 2 days before it failed it started to whine noticeably, but slightly to where I couldnt pinpont the sound but it was audible in the cabin. The bearing eventually seized and melted the pulley, but no other damage...miracle that the belt didnt snag anything. Stopped immediately and towed her home...after replacement no more o2 sensor codes and a slightly smoother idle.