Lexus IS 300 2001. My vehicle overheated and warped the cylinder head without blowing the gasket. The head was replaced and everything reassembled, but now there is a slight knocking noise and a rough idle what could cause this? Do you think the timing is off?
Hello Jaqualine- as far as the engine knocking; what may have happened is that the engine got hot enough that there was damage to a piston or a wrist pin- as far as the rough idle that could be caused by ignition system problem, bad fuel injector or possibly low compression in one or more cylinders - ignition timing on this vehicle is electronically controlled & the knock sensor would prohibit any timing issues causing a knock- hope this helps- thanks Super Girls Auto.
〉 Answered on Dec 29th, 2009 by Laurie Sarno, Co-Owner at Super Girls Auto