okay so yeasterday i put a full tank of gas in my 1987 n/a. the same grade and from the same place i always go. It used to idle at 1000-1100rpms and no it dies down to 500rpms or lower and almost kills itself. I checked the gas cap, oil cap, oil pressure, vaccum lines, and intake. Anyone have any other ideas? I'm getting ready to check fuel pressure, fuel filter, and injectors later today.

 

Set the TPS; 1V engine fully warmed; SHort the initial set connector (green 1 hole connector located at the battery) then start the engine and set idle speed to 750-1000. remove the short wire from the initial set connector. Go back and verify the TPS setting.

 

actually, the initial set connector on an S4 is a green two hole connector. Located near the battery. Short it by running a wire into the two holes of the connector.

 

Im having the same issue with my s5, I just bought a new tps how would I set it???

 

thank you for replaying. i was in a hurry to write and post this thread. lol i was at work. anyway i left out some other things. its acting like its running lean. i did a fuel pressure test and its running at like 35psi from the pump and it should be at more like 65 ish psi. and when i blocked off the fuel return line then pressure when to where it was supposed to and started running correctly. also, when taking off there is a huge lack of power and pulsating.

 

so update. I changed the fuel pressure regulator. It hasnt changed anything. I did notice though when i was pulling the secondary injectors out that the idle position sensor had a wire torn out. so imgoing to go home after work and start fixing what i can. could the mass airflow sensor have anything to do with this? and whats the stock fuel pressure supposed to be on a 13b n/a?

 

okay so update. It wasnt a fuel problem. According to Alldata online I had low fuel pressure. I replaced the fuel filter, fuel pressure regulator, and fuel pump. After all that she was still running horribly so I stated looking into other possible problems and found that the leading plug for the front rotor wasnt firing. The leading coil had stopped working. After replacing the coil and resetting the idle she is running beautifuly. =D