I have a 2003 acura mdx that we've owned for 2 years. It's probably one of the best cars we've had but in the last 6 months the mpg's have dropped off significantly. It went from getting 22-25 to 15-20. When it's cold it can be a hard start and it idles like it's missing. I've tried to reset the computer but it's made no difference. I live in a small town and I've taken it to multiple mechanics and they always hook it up to their computers looking for codes and find nothing. The car has about 140k miles on it and I'm trying to avoid the dealer. Any help would be greatly appreciated.

 

have you done service on the car? air filter, oil change, spark plugs?

 

have your valves adjusted. they might be tight.

 

yeah, probably needs a valve lash adjustment for sure. Usually it will throw codes before hand but not always. The bad idle is one of the prime suspects of it needing to be done. If you hooked a vac gauge to it you would probably see a low vac reading as well.