My XC90 (3.2L Auto) has started developing a 'stutter' when driving. It seems to be erratic, and can occur when at idle or at highway speeds; when cold or when warmed up. There are no CELs, and on checking with my scanner I can see no codes are being thrown.
I cleaned the MAF, and it made no difference. I then replaced the MAF with a second-hand unit, but again no apparent change. I went back to the scanner, and reviewed the live sensor data, specifically for the MAF. What I noticed is that at idle the MAF would report a spike in the air flow (an extra 3-4 g/s), which corresponds with the stutter. Furthermore, this spike would be immediately preceded by a drop in the voltage to the OBDII module. I'm not sure if these readings are related or not. I've replaced the air filter and ensured there are no blockages in the intake, but still no change.
Does anyone have any ideas what to check next?
Help, Advice, Owners' Discussion and DIY Tutorials on Volvo XC90s. The XC90 proved to be very popular, and very good for Volvo's sales numbers, since its introduction in model year 2003 (North America).
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with it idling and the low voltage symptoms I'd say pull alternator and inspect one way clutch on drive cog and the driving cog on engine. But the occurrence when driving and idle would push towards fuel pressure control issues. I assume your lower voltage readings are on scan tool as voltage it shows. The alternator drive slippage could maybe still be a cause. DOes the voltage drop when it happens when driving off idle?