TOPIC: 2002 GMC Yukon XL 5.3

I did the modification October 14, and then took a road trip the next day. I noticed a lot more power and smoother shifting. I also went from 14 mpg to 17.5 mpg on that trip. When I got back I installed a fuel saver and did some adjusting. The vehicle then went from 17.5 mpg to 12 mpg. After much trial and error and ECU conditioning (read on public documents) I have experienced the following improvements.......

November 4 13.375 mpg
November 5 15.03 mpg
November 6 16.77 mpg

As you can see with 3 tanks of gas I am seeing a steady improvement. I will report more as it improves.

I did the modification and read all the public documents. I then capped PCV, re-routed map sensor to the lowest point of intake manifold on port number 2, put tape on MAF sensor, and reduced and re-routed idle air pathway. 180 degrees from the groove, and increased the gap on spark plugs by 20%.

Frank, Great work with the Yukon! You are doing everything right and utilizing all the information and techniques. It's wonderful to meet another Gadgetman. Nick

Hello Frank, this is Aron Cheek, GadgetmanNebraska, I must apologize for not getting back to you. It looks like you have made some great improvements.

This is great information and thank you for the details of your modification.

It's great to see your determination, and effort with the Yukon.

GadgetmanNebraska Aron Cheek