turbo lag and variation

[Nilao]

First get a inline 5 adapter and insite 5 off eBay. That way you can see what is going on in your ecm and your not at the mercy of the dealership telling you only what they want you to know. There are ways to test the turbo but you need a computer to do it right.

Secondly you need get with unilevers, Mr Hagg, or gearhead to check that tune out. There is so many tunes out there that, even though the mandate is gone, they do it in such a way that allows the engine to damage itself in the process.

Third you need to check the dpf to make sure it was hollow out properly. Some places just drill holes in the filter. Also make sure your egr cooler is still there as it requires for the oil cooler coolant circuit to function.

That's about all I can think of to assist you for now. Other will chime in also.