Altering the MAP signal

[sierra3dr]

I'm not going to be in a hurry to accept this,but have a read
http://www.fuelsaver-mpg.com/tuning-for-mileage

[capri v8 driver]

Why do you want to chance the sensors values?

The ecu is programmed to work within the stock values of the sensor and in case of the ford ecu, the ecu programming checks these sensor values and compairs it to the programmed values, so altering the sensor values will cause alot of problems and will cause the ecu to go in limp home mode.

There is only one correct solution, reprogramming to ecu. 

They are right about one thing, High milage engines have the risk of faulty sensors like the temp sensors, lambda or maf, vacuum leaks because of old broken hoses, wiring problems, ect.

To get the best out of the engine, these problems needs to be addressed first.

What this side offers is a band aid, not a solution. What they try to do is lean out the fuel/air mixture. Well it could work at low rpm, when the engine needs to deliver power, it leans out because of the different values and the ecu doenst know the sensor values are alterd so it doenst compensate for it. Its proven on a dyno and on the road, these "solutions" dont work.

From the site:

We ordinarily expect people to get a minimum of 25% increase in MPG, and 30-35% is our expected average. Some people have gotten 50% or more mileage increases.

If thats true, everone would buy it. Its a scam, nothing more.

[Dave]

It's clever as it does talk some truths but then goes on to give you fixes that simply don't work & can cause major problems.

[tabetha]

I bet all car makers are queing up for this, I mean all those wasted millions to get things right in the first place, you can set whatever limits you want on a ecu, but leaner isn't better, up to a point going a little  leaner under cruise can give a difference but nothing remotely like claimed.