Sorry for the lenghty post but I have already addressed several possibilities that may cause the issue I am having. I have had an engine rattle in my lr3 4.4 v8 that sounds like an exhaust leak for several years now. There are no engine codes or check engine lights and my Gap tool doesn't show anything other than lost communication codes with the BC module. I initially thought it was the exhaust manifold gaskets so I have already replaced them. I realized the sound comes on after a few minutes of driving and it became obvious it is an air/ fuel /temperature issue. When the ambient air temp is hot the noise is worse and at partial throttle and goes away under wot. In cooler weather, the noise is less pronounced. I unplugged my egr one day and the noise went away however I then got a CEL. The previous owner installed a K&N air filter and after reading that the oil can contaminate the MAF, I replaced the MAF with a new LR MAF. When I replaced the MAF the noise went away but only for about 1k miles and it is now back. I am beating my head against the wall trying to narrow my search down without throwing any more money at sensors and such. When I cleaned the EGR it appeared to be fine and functional. I have smoke tested for air leaks and the engine is sealed up perfect. It appears something is not quite right with the air fuel ratios but also not bad enough to pop a code. Is there anyone that can point me in a direction I haven't thought of. At this point I am considering putting a new EGR and or cleaning the MAP sensor neither of which I am excited to tackle.

 

I get a rattle when I start up our 06’ LR3 for a few seconds then that’s it. We also have 2x 08’ LR3’s and they don’t do this so strange. No codes as well.