1. change plugs if damaged or overused by DENSO VKH20 - Already new plugs installed
2. change air filter with any decent brand - Changed last week, using Leppon
3. get a mechanic to spray some injector cleaner in the throtle control and vaccum valve. - Done last month
4. use a decent 5W-30 oil. - using Liqui Moli
5. if the problem is only when using ac (very common in used JDM) than get the ac pressure checked, on a normal day i.e.40C outside temperature your ac pressures should be lower side = 30, higher side= 180. if your are getting something like 250 on higher side than your ac condenser or valve is choked causing the compressor to over work, get it checked -
Now this is something that I need to get checked. Any reliable ac mechanic that you would recommend ?
Although drop in pick is a new thing and could be because of the AC compressor choking, but fuel filter replacement was long due. I have been looking for one for so long but havent found yet.