I have a problem with a IDLE. When I put on the TPS 0.45, 0.5 then idling is not stable, every 15 seconds, it increases slightly, about 50 RPM, then sharply dropped to ~ 750 RPM. IF I put TPS 0.65 then idling is stable .'ll show how to configure?

ps: idling I put on manual

engine is F22B DOHC'96
ecu is P39-N50
car is Accord'94 CD3

and if set fuel pressure on 4kg - idle is perfectly

 

Leave TPS at 0.5V closed throttle and 4.5V WOT.
Stop messing with fuel pressure.
Check for intake manifold vacuum leaks.
Check coolant level.
Check IACV

 

I to think that it could be coolant level but also it there could be an air bubble in the coolant systam too. and +1 to the vaccume leak.

 

I was check this list