Okay so i did my egr delete fixed my broken injector plug. Took truck out for a test drive to find out that my new 4" downpipe is rubbing the firewall and making all kind of noise. I have been reading on here about "massaging" the firewall. Can ANYONE get a little more specific for me. I looked under the search function but everything that came up was on 7.3L. This is really getting to be a pain the a#$. Is this job easier to do on a lift should i just put my factory down pipe back in. Im at a loss of what to do and the noise is driving me crazy.