Ok, big question of mine just came up recently when I tried to accellerate 60-90. Mine is a V-10. So I'm driving down the highway in cruise control at 60/61 mph in the fast lane, some new chevy truck comes up on me going like 80, light/ no traffic. I triple tap the gas pedal (heard/ felt it drops the truck in a lower gear) and mash the gas pedal. It starts accelerating slowly then shuddered in such a way that it felt like my axle was just in neutral before and torquedthe "stationaryaxle" with a driveshaft going at 4000rpm ("hypothetically") and took offaccellerating 60-90 inlike20 sec. I swear the whole gears felt like they got ripped apart. Only happens in cruise control, 60mph or more, rpms go from 18/2000 to 3300 rpm while accelerating. Did this three more times causeit was a fun rush. Any thoughts? BurningRom? is this necessarily healthy for my drivetrain, what causes it...I'm curious now.

 

My first thought is throttle position sensor because mine acted wierd just in cruise: not nearly as wierd as yours though. My second thought is the fuel pump. The tps is pretty easy and inexpensive to change: just ackward to get at. If it has more that 100 000 km or 60 miles on the original fuel pump it likely needs to be replaced. Good luck I hope you figure it out.