Hi my 95 850 turbo recently started having this issue. I got the following codes. P0 300, P0 301, P0 302, P0 303, P0 304 (i guess all 5 plugs are misfiring) Also P0 102 and P1 310. Please Helo

 

You can also pull the codes using the diagnostics port up by the front/passenger side of the engine bay vs using the OBD codes. (one of the nice things about the 94/95 850s) Check out volvotips.com for how to pull codes and get the Volvo specific descriptions.

So for your codes, the 0300s are saying you have misfires, the 1310 suggess something is amiss with the coil and P0102 says something is out of range on the MAF. What I'd do is start by looking at the date code on the wires. If older than say 3 years start with a "stage 0" tune up - Cap/rotor/wires/plugs and see if it runs fine. Its possible the coil could be bad as well. Finally for the MAF code, start by getting some CRC MAF cleaner (not carb cleaner) and try cleaning the MAF, intake, throttle body and perhaps the IAC valve (if the MAF is gunked up, might as well clean all). I always look around for possible vacuum line issues as well when I do a tune up...

There's some DIY vids on Youtube to help here on how to remove and clean the MAF.

 

Thanks a lot Mt6127

 

Quick update. I got the car scanned with a professional grade scanner and I was told that the rear O2 sensor signal was the only reading. Could that be the cause of the misfire? Also, the speedometer is fluctuating when the yellow arrow flashes.

 

I changed my rear O2 sensor. However, the transmission arrow flashes and the speedometer goes up and down or not work at all.could this be the acceleration sensor acting up?

 

Could be a sensor but you may want to research issues with the ABS module. Not all scanners will pull codes from the ABS and the speed sensors and transmission CPU talk to the ABS... The ABS module has a circuit board that is prone to cracks in the solder joints which can lead to codes or other odd behaviors.