Lightbulb [Q] WIFI Issue

I use XT1033. I had kitkat 4.4..2 installed. Last month I updated to 4.4.4 via OTA. The issue I was facing from then was weak WIFI signal. I cannot connect with WIFI from the room beside the router. But the issue wasn't in 4.4.2. However I did a factory reset, wiped cache/dalvik cache etc. I changed advanced wifi settings (untick "Avoid Poor Connection"). No luck so far. If I flashed with any of the CM based ROM, the issue gets disappeared.

In 4.4.2 I was facing another issue. Sometimes no audio during voice call. That was completely gone in recent update. You guys please suggest me a solution.

PS: I love CM but cannot leave stock because Total Recall Call Recorder doesn't work in custom ROM. So I prefer Stock ROM.

Thanks in advanced.