Toolman4

The premium didnt help. It happens at 1200 rpm just after a shift and definitely sounds like det ping or like not getting enough fuel. Ran great before the program. If I let off and slowly roll into it at that 1200 rpm she rattles. With the better mileage I know they took away some fuel. I wonder if they could just add back a little fuel at that rpm.

So i did the recall for ecm reflash on my at4 with cold air intake. Gm did it under warranty. My mileage definitely increased but i am now getting a knock at low rpms. Only right after it shifts. Put premium in it and same thing. Doesnt do it when at cruising speed or on it hard... just right after an easy shift. Its very slight, but never had the issue before the flash and it ran great. Anybody else notice this?

Had the flash done and now have what sounds like engine knock at low rpm. This is on 89 octane. Happens when shifting..... not in a gear cruising. Anybody else notice this? I gained about .5 miles to the gallon and pretty sure it leaned it out. I will have to try it with premium.

I dumped the paper for the recall #, but mine was a 19 at4 and this was the first I heard of it. It seems to me it would be running lean without the adjustment, but they make it sound like it's a epa rich condition. I get 19, 20 running down the road with the 6.2 and factory lift so I don't want to affect the mileage or power.

Does anyone know how this reprogram affects performance. Is it running rich since it says it might exceed emissions standards?