well i am now on my 5th burn and all is well so far..... so a big thanks to all on these boards for you info.

i have done a search but have not found the answere to this Q,
for highway mode there is a constant " maximum time in highway mode" wich is currently set for 60 seconds....... is there a min or max setting that should be used?

i do fair amount of highway driveing of about 4 hours at a time on the weekends

 

It works in conjunction with the lockout timer. When in HM, the ECM will stay in HM for the time length you specifiy in "Max Time" and then drop out based on the "Lock Out Timer". If you set the "Lock Out Timer" to 0, it will stay in HM permanently.

The whole concept is to cycle in and out of HM to keep the cats from over heating. However, I know people that have it set to run all the time and have done so for a number of years with no problems to their cats.

This is one of those "do so at your own risk" type recommendations.

 

It is important to drop out of highway mode for short periods of time. This is to keep the fuel calibration in check. If you stay in highway mode without ever dropping out you can actually start to run richer then stoich.

Try 90 seconds in and 15 seconds out, rinse & repeat.

And you will definitely see an increase in mileage with the lean cruise.

RBob.