Okay, so now I have went through 4 intakes that were no good so decided to replace all the gaskets in the one I had. Now for the people who were not aware of the problem I was having, My car runs fine when driving it had good power and everything. At random times RPMs would drop from 750 to 500 and bounce back and forth. It would do this when first put into gear or when I came to a stop light. I took the manifold off replaced all the O-rings and gaskets in it. I replaced the IACV. I have replaced another sensor that looks like some sort of temperature sensor. This is on an 89 Civic DX DPFI. I’m not interested in doing a MPFI swap cause it’s an automatic and its my daily driver. I checked and replaced all vacuum lines and double-checked for vacuum leaks. I’m stumped I don’t know what it could be. Any more Ideas. I have also noticed that sometimes if it starts doing it I can turn the radio off or the heat and it will stop. I have had the Alternator tested. I have replaced the plugs wires, cap and rotor button. No check engine Light codes. When I replaced the gaskets I used another manifold and the same throttle Body. Now I would have changed throttle body but the 4 I have are scrap they are no good.

 

i dont know about your electrical problems, but

the loppy idles sounds like the fuel pressure regulator

 

Is that located on the throttle body

 

i dont remember , does the duel point even have fuel pressure regulator?

im sure it does somewhere

my si had the lopy idles cause the fuel pressure regulator went bad