This problem has bothered me for a long time. If someone can help me to solve it, I am really appreciated. My car is 1995 volvo 850 GLT engine type B 5254 S automatic. Several months ago, when I bought it from my good friend I took off air intake box cover and lost the hose between intake box and throttle to try clean throttle, so I disconnected MAF sensor and cleaned throttle. After cleaning, I put them back and the engine check light turned on from that time. I have been to dealer to check the error code and they told me the problem is MAF sensor (1-2-1, I have checked again by my self). Although I doubted is the MAF problem (because I just clean throttle, I didn’t do anything for MAF), I followed the dealer suggestion to buy a MAF sensor (used part). After I installed it, the engine check still on and I felt so stranger, so I put my MAF sensor (original) in my friend’s car (S70 1998) and there was no any problems in my friend’s car and the engine check light didn’t turn on. I have checked the wire that connects MAF sensor and it has a good shape. My car doesn’t have any problem except engine check light. Does this fault signal result the low MPG? My car seems to has very low MPG about 14,15 MPG in city and 23,24 MPG in highway. And I feel engine’s vibration especially when I shift to D (from N to D). Mechanic told me can try to replace engine mounts. Do I need to change all of engine mounts or just change individual?
Thanks