I was one of the first to bring up the theory of piston slap. My engine started making this noise after my second oil change at 1300 miles, using Penzoil 5W-20. At first, the rattle was limited to just 3200 to 3400 RPM, and it was summer here in San Diego. I changed oil again at 3000 miles, again using 5W-20. At 6000 I switched to Mobil 1 5W-30. The dealer told me this is what they used. Now its cooler and the rattling extends to 4000 RPM.
However, recently, after the engine was fully warmed up, I could easily duplicate the engine rattle on the freeway in 3rd gear at any RPM by feathering the throttle. This is why I think its piston slap because the pistons are under very low load, thus allowing them to vibrate. Obviously, this is a serious problem and I don't think anybody from Ford could say this is normal. I am very reluctant to have the dealer begin probing, I went through a nasty probing mess with my 99 Cobra that Ford ended up buying back. At this point, I think its best to wait until Ford comes out with a solution.
The car is an absolute blast to drive, so I'm going to continue to enjoy it. As the Greatful Dead sung, "I maybe going to hell in a bucket but at least I'm enjoying the ride..."
TB #2127
However, recently, after the engine was fully warmed up, I could easily duplicate the engine rattle on the freeway in 3rd gear at any RPM by feathering the throttle. This is why I think its piston slap because the pistons are under very low load, thus allowing them to vibrate. Obviously, this is a serious problem and I don't think anybody from Ford could say this is normal. I am very reluctant to have the dealer begin probing, I went through a nasty probing mess with my 99 Cobra that Ford ended up buying back. At this point, I think its best to wait until Ford comes out with a solution.
The car is an absolute blast to drive, so I'm going to continue to enjoy it. As the Greatful Dead sung, "I maybe going to hell in a bucket but at least I'm enjoying the ride..."
TB #2127