MY04 GT cruise control problem

[timmo]

Hi, first time posting on here. The car is a MY04 GT liberty 5spd. Lately when driving with cruise control set the motor is hunting and you can feel the car lurching. It runs fine otherwise. I've read that 02 sensors can be a problem but there is no CEL. Only modification from stock is cat back exhaust. Can anyone help or is the best option to go to a dealer with diagnostics?

Cheers

[Dropz]

Getting a dealer to look with the Subaru select monitor would be the best option, but yes it could be O2 related without having a CEL. It could be a knock sensor, and rarely, but not unheard of, brake light globes.


Even if all the brake lights are blown it is worth replacing them, I had an 04 gt come in with lack of power, after hours of diagnostics with no result the foreman suggested we change the brake light globes, even though none were blown. So we did, and BAM! She pulled like a kid on raspberry cordial! Reason being that the libs are electronic throttles, and so the ecu uses inputs from all the safety components, ie brake lights, cruise control, wheel speed sensor etc to control how much to open the throttle.

[mincedmeat]

Getting a dealer to look with the Subaru select monitor would be the best option, but yes it could be O2 related without having a CEL. It could be a knock sensor, and rarely, but not unheard of, brake light globes.


Even if all the brake lights are blown it is worth replacing them, I had an 04 gt come in with lack of power, after hours of diagnostics with no result the foreman suggested we change the brake light globes, even though none were blown. So we did, and BAM! She pulled like a kid on raspberry cordial! Reason being that the libs are electronic throttles, and so the ecu uses inputs from all the safety components, ie brake lights, cruise control, wheel speed sensor etc to control how much to open the throttle.

I dunno, that was more likley a problem with a bad earth.
When was the last time it was serviced? Its could be a problem under load. Ie. cruise control on in 5th at 40km/h
A good service including upper engine cleaner might do the trick

[Dropz]

Service history was all fine. Once we changed the globes it went perfectly.

[timmo]

Thanks for the replies. Interesting mention of sensors. The car recently had 2 wheel bearings replaced, just wondering if thats related. It hasnt had a subaru service for a while so i think i should get that
& see if they can diagnose