I replaced my MAP sensor and did a tune up on my truck this weekend. My truck runs stronger now and appears to be getting a little bit better MPG. Today I ordered 2 new upstream O2 sensors from the NGK website. I hope they will help to increase the MPG now. I still have the original O2's and they have 110,000 miles on them. I think they are getting lazy. I can smell the rich exhaust for the first few seconds when I start my truck but I have no codes stored. I keep reading about how bad Bosch O2's are and they don't work well on Dodges and some other vehicles. Is that really true? Has anyone had good luck with a Bosch O2 sensor? Has replacing the O2 sensor, regardless of the brand helped anyone's MPG? By the way, my sensors were only $30.00 each online. I will have to wire in the connectors from the old ones, and I paid a little extra for 3 day UPS shipping. But still it cost less for one new one at the dealer, and even less for a Bosch from Advance or Autozone. Any info is appreciated, I'm just trying to get my truck to run the best I can and hoping we don't see $4.00+ for gas this summer. It goes up more every day here. Truck is a 2001 Dodge Dakota w/3.9 V6 and 5 speed manual. 110,000 miles on it.