I have a 08 Edge with 157,000 miles on it. The trouble started last summer, but the local dealer could not find the cause despite several codes and my descriptions. I thought I had a transmission problem, but as fall arrived the problem went away. Now with temps in Missouri climbing back into the 80s the same problems have once again began.
I make several trips to Louisville KY and back each year. On one of the trips last summer the car began to experience several problems.
1. The RPMs will begin to jump up and down about 1000 rpms. The car will also lag as if it was taken out of gear.
2. Some times the car will simply jump as if you popped a clutch. Sometimes this is violent enough to almost give you whiplash.
3. The problem seems to appear more often if I am using the cruise control. When using the cruise control you will also see fluctuations in the speed in both directions between 5-10 mph.
4. As stated above these problems appear when the outside temp is in the 80s and increases in frequency as the temp increase.
5. At the end of last summer the problem would arise after about 60-90 mins of driving. After 3 or 4 incidents on a trip the next occurrence would trigger the check engine light.
6. If I pullover for 10 mins to let the car cool down the problem immediately stops until the car is driven for another 60-90 mins.
The dealer found the codes generated to be of no use. We focused on the transmission, but found no signs of damage and even after new fluid and complete inspection the problem occurred on the next trip.
I now realize that outside temp is a factor in whatever the problem might be, but I'm hoping someone else has experienced this same situation and can give me some advice.
Thank you
