Live Chat: 1998 Honda Civic LX D16Y7 195k Automatic. Initially had a rough/surging idle problem, cleaned throttle body, injectors are good, new spark plugs, IAC valve good. Car idles fine but running conditions are crap. Loses power at seemingly random times. Finally ran diagnostic tool and came back with P0172 System Too Rich (Bank .1). Previously threw a P1456 But that has since gone away and not returned.
Freeze Frame Data is as follows Throttle Position: 9.8% Engine RPM: 1261 Load Value: 19.6% Map Sensor: 21 KPA Coolant Temp: 197 Degrees F (Water Pump issue [resolved]) Intake Air Temp: 109 Degrees F Short Term Fuel Trim (1): o.o% Long Term Fuel Trim (1): 3.9% Short Term Fuel Trim(3): -100.6% Long Term Fuel Trim(3): -100.6% Speed: 34 MPH Fuel System: Open 1 Fuel System 2: N/A I am absolutely stupified and don’t want to spend more money replacing parts that don’t need it.
I almost threw away $170 on an IAC valve that I didn’t need. Please!!!!! HELP!!!!!
If those fuel trim readings are correct (-100.6%) then you have an extremely rich mixture. Something is just dumping fuel into the system or you’re getting absolutely no air into the combustion mixture. I notice you say the injectors are good, but how do you know?
What testing was done on them. This type of problem is usually a fuel injector that is stuck open and just dumping fuel at all times. You might want to check that out again. Otherwise, look for anything restricting airflow including a clogged catalytic converter.