I have a 95 Lexus sc400 I just replaced the ecm, it sat 8 months, now check engine light is on and it surge idles from 1200-1800 rpms. When I pinch the vacuum behind MAF it idled down and stops surging, I cleaned idle control and egr, I cracked the fuel cap and fuel was at the cap. I've checked all vacuum lines by missing brake clean I have no leaks I have noticed. Any ideas?