Bucking F 50 cruise control

[StarPD]

Here's another unusual problem on my new-to-me 2005 Q45.

The cruise control works fine on level ground and on light to moderate inclines. Going up steep inclines, it works fine.

But going down steep grades, it bucks and jerks,only on cruise control.It feels like someone is turning the ignition off and on every second or two, or like the trans is kicking down and back up again rapidly.

I've tried turning the cruise off, then on again, several times. I can't seem to make it stop doing this, and it's maddening. To avoid it, I have to turn the cruise off on steep downgrades. I've never had a problem like this in any car I've owned, including two previous G50s.

The dealer can't duplicate the problem, and the nearest steep grade is around 40 or 50 miles North of Phoenix on Interstate 17 to Flagstaff, where I discovered the problem. They checked out whatever they could, trans and cruise, and can't find anything wrong, no codes.

I called Infiniti Consumer relations, and they told me to just take the car back to the dealer and get someone to go for a 100 miles round trip ride with me.

So I'm getting the old "Gee, I never heard of THAT before" routine.

Has anyone here ever heard of anything like this before?

[Q45tech]

A tech needs to get paid to feed family and Nissan doesn't pay unless something is found and nothing for diagnosis so offer to pay for the techs time say $50 CASH for the ride, if you really care that much about solving the problem.

Esoteric odd problems are always difficult.............takes financial cooperation from all parties.

As Jay Leno to loan you one of his half dozen salaried technicans/experts he keeps to maintain his cars.

Are you setting the cruise speed above 70 mph > what speed setting?

[StarPD]

A tech needs to get paid to feed family and Nissan doesn't pay unless something is found and nothing for diagnosis so offer to pay for the techs time say $50 CASH for the ride, if you really care that much about solving the problem.

Esoteric odd problems are always difficult.............takes financial cooperation from all parties.

As Jay Leno to loan you one of his half dozen salaried technicans/experts he keeps to maintain his cars.

Are you setting the cruise speed above 70 mph > what speed setting?

AFAIK, techs are paid flat rate, and there is no flat rate for customer rides. I was thinking of asking the Service Manager to go along with me, and offer to buy him lunch.

Cruise was set on 70 MPH. When I take the ride, I'll try different speed settings; 65, 70, and 75.Good point. Thanks.

[maxnix]

Yeah, service writers are good to get on your side, so it might work.

A tech will be losing money while he is riding with you.

Nevertheless, your complaint is valid, so get it written on an RO.

[StarPD]

Yeah, service writers are good to get on your side, so it might work.

A tech will be losing money while he is riding with you.

Nevertheless, your complaint is valid, so get it written on an RO.

Actually, the service writer is busy writing ROs and ramrodding jobs. They are on commission too. I was thinking of the Service Manager, who is on salary.

It's already been on one RO, and will be on another when I do it. I was planning on calling ahead and making an appointment with him for when I bring the car in two weeks from now at the time I get the cooling system flushed and the diff lube changed.

[maxnix]

Good plan. Good luck.

[StarPD]

Good plan. Good luck.

Thanks.

I will of course, report on how this shakes out.Sooner or later, I suspect that someone ese will encounter this.