Surging on overun

**nismine01** · 21st April 2016, 11:45 AM

My Disco TD5 auto hunts badly (surges) when cruise control is set and we reach the point of overrun (down hill) where the computer seems as though it is confused.

Despite the speed being virtually perfect with the setting, the engine accelerates hard only to back off just as harshly.

Were I accelerating very hard it would almost seem like an over boost situation, but it really is a cruise situation.

Any thoughts out there please.

Mike

schuy1 · 23rd April 2016, 05:50 PM

Hmm, Mine has started doing something like that. Though not on cruise, although hard to say as I dont use it much. More on general over run , throttle off for an intersection or a dip and it will hunt a couple of times, but not every time. I am suspecting its either the boost modulator or a slightly sticky waste gate. Will check them out when I have time.
Cheers Scott