i have a 98 s70 turbo with 330 000 km. runs really good. but after about 600 km or driving the check engine light comes on and the car starts running poorly for a minute, then runs fine. every once and awhile it will run poorly, un even idleing too.
the code that is present is P0108 Manifold Absolute Pressure/Barometric Pressure Circuit High Input. i tried another used sensor (located behind passenger head light) that worked fine in the car it came from(XC70) and the s70 did the same thing setting p0108 code. also the xc70 still ran fine with the sensor originally from the s70. i did not swop them back.
i dont want to spring for a new sensor if it wont fix the problem.
I also tried another used air mass meter that was working from the car it came from, and that did not change a thing.
any ideas?

 

First thing I'd do is get an alldata DIY subscription for your car, and go to the troubleshooting charts for that code- alldata has Volvo's original chart. There very well could be a problem in the wiring to that sensor. Keep in mind- codes don't tell you what is wrong with the car- they tell you what sensor is reporting a problem or where the ECM thinks you should look. Good luck!

 

i did check the resistance between the snensor and computer, no problem there.
i dont know any one who has all data.