[Tylinol]

This may be a trivial issue, but I've noticed that my Milano often surges moderately at speeds below 20mph. With my foot steady on the pedal in 1st or second gear, I'll get a sort of surge-roll-surge-roll-surge-roll at steady intervals. Putting the clutch in and rolling at the same speed does not result in any surging, so I don't think it's brakes/out of balance wheels.

Anyone know what could cause this?

 

[NMMilano]

I would try changing the O2 sensor. As its "hunting" for a setting the mixture is changing. It's only pronounced at low throttle settings.

 

[kredden]

Before spending money on a new O2 sensor, I'd disconnect it and see if the problem gets better first.

Kevin

 

[NMMilano]

Before spending money on a new O2 sensor, I'd disconnect it and see if the problem gets better first.

Kevin

Good point.

 

[Tylinol]

I finally got around to trying this today. The surging was gone, and the car felt noticeably more alive. It used to hesitate to rev past 2500, but now tachs right up straight to the redline. I'm going to swap out the O2 sensor and probably do a vacuum leak test as well.