Tried all things to diagnostic this issue.
Today, I have replace the ECU with my old S260 ECU, no help, idle drops tiny litlle faster but only tinnnny
So I have changed:
1. 2 new MAF, 1 loaned by the shop, 1 I bought in case shop's has problem;
2. Checked all vacuum multi times with different tech and me just in case;
3. Replaced Multi Function Control Unit, just in case;
4. Check all the fuses;
5. Disconnect battery multi times, even did what Charlix suggest shut down the engine without battery connected to force the ECU to reset;
6. Reset ECU by Kold Fire cable;
7. Replace B300 ECU with my old S260 ECU;
Same same. So on Sat I will transplant my friend's hrottle body to see what happen.
At the mean time any suggestion?