i have a b18a1, on start up idle is about 3000. after sevral minutes it will idle down to 700 RPM, after it idles down, about 1 minute into idle it drops to about 200 and dies. I have port and polished head, Fuel pump, bigger injectors, full exhaust. i also have a high flow fuel rail. It was running fine then just started this about a week ago. i do not drive the car as it is just a project, wanted to see if i could get some help here before i send it to a tune shop.

 

It might be your head its flowing to much cause of the port and big injectors you can try to bump the fuel pressure on the fpr and adjust the flat head screw on the t.b, but you said it was running fine did you run the motor hard untuned??, you might!!! have a slight bent valve are you using the stock ecu? or best case senario you might have a vacume leak or a loose vacume hose.

 

i have checked all vac lines, they are fine, i actually replaced 2 that seemed old, still having the issue. i looked inside the intake manifold and it is severly dirty. i really hope i havent damaged the valves, yes i did run it kinda hard ONE time untuned, yes i am using the stock ecu, and u mentioned bumping up fuel pressure, i think thats a bad idea, i bought a air fuel ratio gauge just to see and it runs rich as hell all the time but leans out at about 5500 rpm.. i plan to replace the intake manifold and throtle body next hopefully this will resolve the issue as i think it is getting too much gas not enough air from the port and injectors and the rail. what are the 2 things you were talking about the flat head screw? where is that? it dosent ring a bell?