I have a 2008 with the 3.7 engine and automatic transmission. When the transmission goes into overdrive at about 45 MPH, without anyinput from the accelerator or change in grade, the RPM's will settle in at about 1700 RPM's then after about 2 secondswillshoot up to around 2100 and stay there. I have tried this in D and also 3 with the same results. I havealso noticedwhen decelerating I get the samespike but it quickly returns to normal. My 2006 with the 3.5 did not do this. Only mods are a Magnaflow Catback exhaustand an Airdoc intake. I am 99% sure it was doing the same thing before the mods. Is this normal or should I have it checked? Thanks, Randy

 

I think I may have solved my own problem. I started thinking Throttle Position Sensor and how it works. There has got to be a rheostat or potentiometer at theaccelerator pedel that senses it's position. This vehicle isa new 2008that came from a dealership in Atlanta. It could have sat there in the humid weatherfor over a year before my dealer in NC went there to pick it up for me.I was thinking of oxidation on the rheostat, compounded by lack of use. With the engine off, I worked the accelerator pedal up and down several time fairly quickly. After about 20 stops and starts, the RPM spike seems to have gone away. Does this make sense? I will post later to update.

 

It's back.. In overdrive under a slight pull between 45-50, the RPM's will sometimes cycle up and down about 300 RPM's.It is still inOverdrive and has not downshifted. Has anyone else noticed this?

 

i just noticed this same problem about a month ago...

mine is an 06 with about 38k miles..

i am taking it to the dealership for the homelink replacement...while im there i will ask them to check into this...

i will let you know what they find out..

 

My dealer is 2 HRS. away and I don't think it's worth a special trip. I'm like you I'll just have it checked when I'm there for something else. It is annoying. Seems like most of my driving is in that range and it gets on my nerves. Maybe I'll put the stock exhaust back on it in the meantime. At least I won't be able to hear it : ) plus I can turn the radio up. Let me know what they find on yours.