my buddy was doing 70mph down the freeway and the truck decided it would only do 30mph. he put it in neutral (while rolling) and it started revving so, he killed it and safely pulled to the shoulder. he got a "power engine down" light (havent heard of that light). is this the truck going to "safe mode"???? it happened on sat and he hasnt had the trouble since. im sure there is multiple suspects for this but, has this happened before to some one? what could be the problem??? the truck is an 07 classic silverado 4.8. about 4-5 months ago i tuned it a little bit by lowering torque mangement (didnt remove it completely) and added a small bit of timing while i was in texas. i dont have a log.

 

Yah it sounds like it went into limp mode. Something is definitely wrong there. You need to scan the trouble code, if you can get me the code i have access to GM Dealerworld and can tell you a much more detailed description of what might be going wrong. In the mean time, i would return the tune to stock and see if it goes back to normal, scan and clear the codes, but most importantly see what's wrong, you need to find out what code it is.

 

putting it to stock is going to be hard because hes in texas and im in maine. ill see if he can have it scanned but, he disconnected the battery for an hour and reset his light. it should be stored still shouldnt it? if he gets a code ill definately hit you up. thanks

 

Well if there's a problem it will come back and so will the light. Go to Autozone or something and borrow an OBDII scanner, it's free once you return it.

 

i talked to him yesterday and he knows a buddy at the dealership. so i think they are going to scan it when it happens again. i told him to find out now but, he wont listen. i know it cant be good when your truck does something like this.

 

Could be the truck exceeded one of the torque limits and entered that mode. Look for that in the calibration file you have. Next time you see him, you can further investigate what tripped that error.

 

that would make since but i compared the stock tune and our tune and found nothing that would trip it.