# What causes valve chatter? **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [August 8, 2019, 10:15pm UTC](https://community.cartalk.com/t/what-causes-valve-chatter/146306 "2019-08-08T22:15:42Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Austin\_Travis](https://avatars.discourse-cdn.com/v4/letter/a/bc79bd/32.png) [@Austin\_Travis](https://community.cartalk.com/u/Austin_Travis)\ **Post date:** [August 8, 2019, 10:15pm UTC](https://community.cartalk.com/t/what-causes-valve-chatter/146306/1 "2019-08-08T22:15:43Z")
I have a 2004 3.9l v6 Mustang with 125k miles and the valves started chattering with 87 octane a few months ago so I just started running 93 octane and now they’re starting to chatter with 93 octane. The chattering doesn’t appear until driving for after about 30 minutes. The chattering starts with a very light load on the engine and then disappears after about 3500 rpm. It is the loudest when accelerating around 2500 rpms and at highway speeds with even the lightest touch to the throttle. I have new spark plugs, there are no exhaust leaks, good egr, and the imrc actuator rods are connected. Does anyone know what could be the cause of the valves chattering? And would torquing the rockers possibly have any effect? Thanks. ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [August 8, 2019, 10:17pm UTC](https://community.cartalk.com/t/what-causes-valve-chatter/146306/2 "2019-08-08T22:17:59Z")
I think with all the threads you have on this thing it is just worn out. Might be time to update to a newer Mustang. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [August 8, 2019, 10:39pm UTC](https://community.cartalk.com/t/what-causes-valve-chatter/146306/3 "2019-08-08T22:39:24Z")
I don’t know what you mean by “valve chatter”, you’re probably hearing knocking/pre-ignition. Nothing with valve adjustment would be affected by different octane gas. But why the new thread? ---
**Author:** ![It\_s-Me](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/it_s-me/32/12660_2.png) [@It\_s-Me](https://community.cartalk.com/u/It_s-Me)\ **Post date:** [August 8, 2019, 10:46pm UTC](https://community.cartalk.com/t/what-causes-valve-chatter/146306/4 "2019-08-08T22:46:35Z")
@Austin_Travis Including this thread, You have 4 different threads for this same problem. Your chances of getting help go down with each thread you start. If changing fuel octane made the problem go away, it’s not valve clatter, it’s ignition timing. > [@Rattling/chattering noise from engine bay on mustang](https://community.cartalk.com/t/rattling-chattering-noise-from-engine-bay-on-mustang/143161): > > I have a 2004 automatic 3.9l mustang and it makes a rattling/chattering sound that sound like its metal on metal from the engine bay and it sounds like it is directly in the center of the engine. This sound only is present when the engine is in 3rd gear or higher and only happens between 1500-3000 rpms. It also will only happen if I hold my foot in a certain throttle position. If I let off it will stop and if I floor it, it will stop making the sound. There is no power loss at all or no noticeab… > [@What causes valve chatter?](https://community.cartalk.com/t/what-causes-valve-chatter/146306): > > I have a 2004 3.9l v6 Mustang with 125k miles and the valves started chattering with 87 octane a few months ago so I just started running 93 octane and now they’re starting to chatter with 93 octane. The chattering doesn’t appear until driving for after about 30 minutes. The chattering starts with a very light load on the engine and then disappears after about 3500 rpm. It is the loudest when accelerating around 2500 rpms and at highway speeds with even the lightest touch to the throttle. I have… > [@2004 v6 Mustang Timing is too advanced](https://community.cartalk.com/t/2004-v6-mustang-timing-is-too-advanced/144728): > > I have a 2004 3.9 Mustang and about 10 months ago the valves started to ping/ spark knock/rattle so I just ran 93 octane until I had time to mess with it. The 93 octane used to completely quiet it and now it’s loud after the engine is warmed up with any load on it, even with 93 octane. Its throwing a p1336 (cmp misaligned. But the code definition is, ckp and or cmp input signal to the pcm concerns.) I’ve changed the crank and cam sensor and the cam sycroniser assembly. However, when turning the … > [@What will caused advanced timing?](https://community.cartalk.com/t/what-will-caused-advanced-timing/146244): > > I have a 2004 v6 3.9l mustang and the timing is advanced and causing the valves to ping/chatter once the car is warmed up. It’s really bad with 87 octane and not as bad but still present with 93. I have replaced the cam sensor, cam sycroniser assembly, and the crank sensor. The car is throwing a p1336 code and the cam assembly was set at tdc with the alignment tool that came in the box. All of the wiring seems fine and the problem is that turning the cam sensor does not change the timing. If any… ---
**Author:** ![Austin\_Travis](https://avatars.discourse-cdn.com/v4/letter/a/bc79bd/32.png) [@Austin\_Travis](https://community.cartalk.com/u/Austin_Travis)\ **Post date:** [August 8, 2019, 11:43pm UTC](https://community.cartalk.com/t/what-causes-valve-chatter/146306/5 "2019-08-08T23:43:46Z")
I apologize for posting multiple times but the main reason for this thread is that I have incorrect assumptions in the past ones, as it seems I still do, and this time I was asking a more general question because I have resolved other issues in the past ones threads and wanted to take other factors out do the equation. Clearly I do not know much about timing and I am trying to fix it and figure it out myself. Also, I did not know that once a thread is posted that it doesn’t just move away and disappear after a few days.