It seems like it may only be in colder weather...but my car has been having difficulty shifting lately.

When going up a hill, not a huge hill but more of a gradual hill, my car dosen't always shift. 1st gear is fine, 2nd is fine too but going from 3rd gear into 4th dosent always happen so smooth. Once I reach the top of the hill, or the ground at least levels out to a reasonable level, the car will keep going in third gear all the way to around 3,000 RPMS. If my speed is not continuing, (Usually at this point its about 40 mph) it will hang in third gear for 10 or so seconds. Backing down on the throttle only drops the RPMS, it does not always make it shift. It will shift into 4th eventually, but there is a good 10 seconds or so of the car running at 3,000 RPM when it should be in 4th. If I shift it to the next gear using tiptronic, the car will stay in 4th and runs like it should. Any ideas?

 

Has it always done it?

I remember reading that the Tip trans has a mode that sense when you are on a hill and changes how it shifts to help you maintain speed on the grade more comfortably.

 

I'm fairly certain it has. It just seems that when the engine is cold, the problem is worse? I'm not saying the engine should downshift on a hill, but once I reach the top of a hill, and am starting to go down, the engine still has not shifted to 4th gear. It seems that its taking longer than it should. I know I have an exhaust leak, but I doub't that would affect it.

On an unrelated note, would the exhaust leak affect my MPG? It's been around 16 as of late. I just had a new thermostat installed to try and fix the MPG issue...

 

Also in this cold weather you have to let your car warm up properly. Can't just gun it and go. Fluids are thick and won't run smoothly.

 

firegod, yes an exhaust leak can effect your mpg, depending on where it is in the exhaust. Your ecu relies on information collected by sensors in the exhaust system directly before and after the cats. It uses this data to optimize the fuel delivery to your car. If your O2 sensor were detecting too much oxygen in the system (becasue of a leak) it would richen up the fuel mixture to compensate and then you get worse mpg.

 

Do us all a favor and tell us what vehicle your driving in the first post. It helps diagnose a problem.

My 96 and 97 A6s delay the shift when the motor is cold. (Some dunderhead in Germany decieded that this was the best way to meet emissions.) If your car is on the C4 platform I would look at the temp sensors or a wire/connection issue.