I always brag on my Toyota, how well it runs, how it still looks good and runs great for amount of miles, but….. My 03 with 325k miles has recently started running rough. I put the OBDII reader on it at AutoZone and it said Mass Air Flow Sensor, so I put on a new one. It did a little better but seems to have gotten worse. Had codes cleared also disconnected battery and hooked back up. It still reads mass airflow. A mechanic said it sounds like the cam shaft sensor. So I changed it today. It seemed to help but still runs rough, sputters, etc. All Coil packs and plugs were changed a few months ago, so they are fairly new too.
What could be the issue? I’m now thinking the timing chain and related comments might be the issue.