I've got a 2000 1/2 ton, 5.3l, LT headers, off road X-Pipe w/ 130K miles.

My buddy retuned with HP tuners about a year ago. The tune worked good until about 2-3 weeks ago. My SES light came on and the idle would dip between 400-500 rpm. My buddy hooked up and said the computer flashed itself back to stock and it was looking for the removed rear O2 sensors and it would send the misfire code. He then tuned it back to where he had it. It worked good for about a week, then it did the same thing. Its done this 3 or 4 times now.

My question does anyone know why this keeps happening or any ideas on how I could do fix it?

Thanks,

Nathan.

 

I don't see how it can possibly reflash itself back to stock. Maybe i'm wrong tho.

Did he say what codes you have? Have you checked your Grounds and pcm to make sure nothing is loose?

 

The tune CANNOT change, the computer cant change its self back to stock.

 

I dont know how it did it. But the first time was after I filled up with Fuel.

 

You might want to get a 2nd tuner to look at your truck, it doesn't sound like your buddy knows. Rear 02's have no effect on the engine in any way. Also, it's impossible for the truck to reflash on it's own.

Check your spark plugs, wires, etc.

 

I hear this often.LMAO I wish more would understand
Just because you get a check engine light,does not mean it is the tune.If you have had the tune for that long without issues,it is clear to see there is a problem with the truck!!!!!!
THE PCM does not go back to stock UNLESS it is physically done by the individual!!!!!

 

HAHA I do bet you hear that quite often, I bet you have some good stories related to this as well. Had my cousin once tell me his tune had changed in his truck because his transmission was not shifting right.

 

LOL I have had many of your cousins.LOL
Yes,some are very unreal LOL But thats part of it!!

 

When was the last time you cleaned the throttle body?

 

Im in the service and out at sea so I cant get the codes for acouple more weeks. Its been about 6 months of driving since I last cleaned the throttle body.