When i'm driving 70 on the highway the thing shuts off the learn control. The BLMS quit changing and it apears that the o2 voltage drops to the lean side. Has someone enabled highway mode on my chip? thanks in advance!!

 

Highway Mode is in the stock chip, but you have to be over 55 mph, coolant over 185 degrees F, and LV8 under 140. Looks like you met all of those conditions. In the wonderful world of DIY PROM-burning, you can change those parameters so that you're in HM more often.

 

Does the commanded AF ratio displayed on your scan tool change? What does it drop to? There are certain circumstances where you get a leaner AF ration (generally 15.2:1) due the DFCO.

Some custom eprom writers DO enable HMF, so it is possible. Check your commanded AF ratio.

 

My scan tool doesn't display the a/f ratio numerically it just shows the o2 voltage. On my A/F ratio gauge the lights drop off the gauge toward the lean side. The ecm shows very low voltage at the o2 like in the double digits. It's been like this for a long time and the plugs don't look white or anything.