My 99 Ranger 3.0 flex-fuel has 115k on it and since around 60k it has had a metalic chatter that is most evident at around 2100 rpm's, which is coincidently the average rpm at my highway or main travel speed. It isn't a constant chatter but most heard on the down side or dropping back down to that rpm such as when backing out of throttle or cresting a hill. It has a short chatter or rattle at cold startup but haven't been using Motorcraft filter, will try next oil change. It seems quiet or not noticable until engine gets warmed up. Someone told me it sounded like a piston slapping but wouldn't that be the opposite? Rattle when cold stop after warm ? Looking to sell it but who will buy sounding like this ?!!! Please advise. Thank you

 

Might be a timing chain rattle, but I'm not sure on how common it is for that motor Piston slap does normally reduce with increased temp. Seems to me I remember something from years ago about torque converter chatter with regards to the lock up system. And that It was not evident till warmed up. Somebody'll be along to support or shoot it down.

Fred

 

Are you sure it's not something stupid like an exhaust heat shield? Or loose guts in a catalytic converter?

When the truck is cold, crawl under it and smack up against various parts of the exhaust with your hand. Pay special attention to the converters.. you might be surprised.

 

Good point, that was actually in a couple of threads lately.

Fred

 

Thanks for the replies, but it is definately a metal on metal tapping or knocking, I hesitate to say knock though cuz it's not that strong, like I said " chatter" is the best description.

 

May be something in the valve train then. A lifter tapping or something if it sounds like rather light tick almost, not a harder/solid sound. I've noticed the earlir very minimally in my motor since about 145K, but not that early tho. You ever try running the E85 through it? It may also be pinging in the engine from the octane level if the computer is reading the octane level wrong.

 

No haven't tried E-85 don't have a source near by, but one mechanic that listened to it did say it sounded almost like spark knock.But I just replaced the ECM to fix a spark knock issue.If it is spark knock it doesn't sound the same as any knock I've heard before.

 

Did you ever solve this issue on yours? My 02 recently started doing the same thing.

 

On my '03 I can hear a definite spark knock at certain rpms on the highway with certain brands of gasoline.
I run name brand 87 octane as a rule.
I recently bought gas from a Circle K and believe the gas was Citgo.....horrible spark knock, after I burned 1/4 tank I topped off with 91 octane BP and all is well.......seems the 3.0 in general is kind of tempermental when it comes to grades/octanes of fuel....

 

Never fixed it, started at around 63 or 68000, at 221400, still doing it.