Hey Im new to the forum and Ls truck power! Just got a good used 2500HD with lq4 a few weeks ago. Runs good and is getting good mileage/power etc. No start up knock yet? but I do have a slight tick at about 2000rpm and sometimes at idle. Sounds like a lifter/valvetrain tick? I have heard about seafoam and using synthetic but Im looking for first hand experiance. Any help or advice would be greatly appreciated. Its got 176000km and does not seem to use any oil etc. Thanks for the help guys and Im enjoying the site so far.