We have had a random noise whilst driving, it sounds like we're going over a cattle grate. No change in revs. Then fine again. Mechanic told us nothing shows up on machine codes. Then on the weekend coming back from a 2 hr drive it revved up to 3 and then suddenly the power (k's) just kept dropping. Sat on the side of road waiting for rac, guy turns up and cleared a pending code and couldn't see anything else as he didn't have a computer to plug in and because we had a young child in the back we couldn't get it towed! Just told us to drive it back at 80- 90ks then take it into shop the following day. Ended up that we were driving at about 40km as it wouldn't get past that and then only just made it into driveway, after power wouldn't go back up it just decreased and decreased to about 20ks.

Had it towed, Mechanic said no faults.

What do we do?