[Baine]

I have a 2005 xB with a manual transmission. I have been experiencing a strange
power loss that feels like the car is going into limp mode. It happens every time
I take a certain freeway cloverleaf ramp. It’s an up hill right turn at about 40 mph.
The car just looses all power and will barely hold 10 mph and wont go over
3000 rpm. After an hour it will sometimes run normal. I have replaced the fuel pump
and strainer. Checked the fuel tank for foreign matter/debris. I have replaced the MAF
sensor. If I park the car down hill and turned off, it has gone back to normal within
a few minutes on two occasions but not always (coincidence?). There are NO codes
or warning lights of any kind. I have about 110,000 miles on the car and it has always
run strong. My mechanic and I are out of ideas. I have driven it over a hundred miles
testing in every cornering condition I can find after the MAF replacement without
problems and then this morning it died again.

ANY IDEAS?

(and I don’t need the comment of “just down take that off ramp”, it’s how I get to work)

 

[ogerdgonz]

Take the off ramp slower then. Actually do this and see if it happens or not to test for my guess below.

I would look into loose wires and connectors that during this corner is being pulled out or loosened.

 

[BestmpgxB]

I also suspect an electrical issue. Try zip-tying your wiring harnesses to strain in one direction, then the other, on subsequent days, until you narrow the problem down to a single group of wires.

It's not that hard to drive to the next on-ramp. I'd do that if I were you. It's a lot safer than trying to merge into freeway traffic at 10 mph, or having your car die during rush hour.

 

[PCH]

Check every factory wire and ground connection that ever got touched when you did any of your electrical mods. Take a close look at the MAF sensor plug wires. They can break under the insulation where they go into the plug, especially if you have aftermarket intake.

 

[msvfisher]

What was the fix for this? I have an automatic 2010 xB doing the same thing.

 

[superbee 4406]

grounds and connections
something simple like a slightly loose battery cable clamp can cause it.

 

[1.8TTony]

Save yourself some time & pay the $$$ for a proper diagnostic evaluation.