cold rattle fix and mpg

[mp5]

Has anyone else who went and got their cold start rattle fixed noticed that thier gas mileage dropped? I had some sort of valve replaced and my ecu reprogrammed about a month ago to fix the cold start rattle(which it improved but didn't eliminate). Ever since, I'm only getting 23.6 mpg. I use to get 27. The dealer looked at it and said they could find nothing wrong.

 

[Blown]

Yeah, my fuel economy went to downhill as well. I'm lucky to get 23. I used to get 28-29.

 

[Cameleon3]

You guys probably rev your car a lot higher than you did when you first bought the car...

 

[fastdrvr23]

My mileage didn't change at all after the fix.

I still get ~31MPG all the time...

 

[Blown]

Cameleon3 - No, actually I don't at all. I have a daily commute where that hasn't changed and I'm not an agressive driver. I always shift at 3500 rpm.

 

[mp5]

My driving style hasn't changed, my route hasn't changed. The only change has been the cold rattle fix. If anyone has an idea on what I can have the dealer look at I would greatly appreciate it.

 

[blynzoo]

The reflash may have, for whatever reason, made you run rich. Take it back now and tell them.

 

[alec172]

Maybe the ECU is still learning. Throught time it may resume to 27-31 mpg.