1999 Tahoe speed sensor ?

[RoyC]

1999 Tahoe 2dr LT 5.7 sfi.
When cruising at around 60mph, the engine sounds as if it is trying to continually change up & down but stops doing it if I accelerate slightly.
Also when I accelerate hard to overtake, it sounds as if it is selecting neautral gear but when I lift off the accelerator it accelerates normaly.

I have recently had a new electronic transfer box fitted and also the inlet manifold water leak fixed.

Please help, what is causing this?
Thanks,
RoyC.

 

[Poe1983]

1999 Tahoe 2dr LT 5.7 sfi.
When cruising at around 60mph, the engine sounds as if it is trying to continually change up & down but stops doing it if I accelerate slightly.
Also when I accelerate hard to overtake, it sounds as if it is selecting neautral gear but when I lift off the accelerator it accelerates normaly.

I have recently had a new electronic transfer box fitted and also the inlet manifold water leak fixed.

Please help, what is causing this?
Thanks,
RoyC.

I don't wanna be a postwhore, but you're in the wrong forum category bro.