Jandar3.2S

I have 2003 TLS 3.2 Pearl white Tan Leather best car I've ever owned or driven but it's driving me crazy. One day smooth as silk the next day misfiring at low rpms and jerky under 3000rpms.
Code reader P300 P302 P303 304 305 306 & P1399
Check engine light came on then VSX light and Triangle. Read and watched about 50 articles and videos for solution thought that because still lots of power impossible 5 out 6 coils or plugs needed replacing only about 25k on plugs so cleaned out EGR Ports and ant tracks/ runways in intake manifold was a fair amount of carbon but no cylinder totally blocked. No change.
Replaced EGR valve, ran smooth for bit but as soon as put under load back to running rough and check engine and VSX light on and still same error codes. Engine seems to run fine over 3000 rpm lots of power but as soon as rpm drops down under 2000 rpm runs rough misfiring i guess according to error codes.
Any ideas car has 245,000 KMS but body and interior still almost like new. Hate to spend big bucks because car only worth a few grand to trade or sell

Karanx7

iTrader: (2)

What kind of spark plugs are you using? What's your idle RPM usually?

Jandar3.2S

NGK spark plugs and around 800rpm at idle

justnspace

iTrader: (1)

have you replaced the coilpacks?