Recently out of no where my car has been running extremely rich my a/f are almost at 10.0 when driving normal and idle its at 13.0. Sometimes it even dies on me at idle after i drive it to work thats down the road. Its a fully built ls vtec 2.0 making 498whp. Anyone can help me out what this could be? Bad spark plugs? wires? Im running a inline fuel filter could it be bad? Nothing has been changed to mess up the tune. Running s300

 

I've had a problem like this before it was the wires in my obd2a to obd1 jumper harness the map sensor wires/pins would come loose. Unplug the ecu plugs and push all the wires into the connector then plug them back into the ecu and see if it fixes it. If not Hook up your hondata to a laptop and datalog it to see what the map sensor read when it's reading 10.0's

 

are you running a gm 3 bar map sensor by chance? this has happened to me twice over the years and it was related to the map sensor shitting out

 

On a GM specific 3bar? Hadn't seen that in 20 years.

 

something like that happen to me, it was the AEM regulator diaphragm with a small puncture.