1996 buick roadmaster stalls like its running out of gas then won't start codes po118 and 420
1 Answer
Rancherodan answered 5 years ago
Po 118 is a coolant temp sensor and 420 is a cat converter not running within the range. The stalling "could be" low fuel pressure. I would check the fuel pump pressure and filter. once that is done and fixed the 420 code might go away on it's own because of the "lean condition" that was created by the low fuel pressure (if that is the issue) . The coolant sensor is on the front of the water pump I would just replace it and be done. Good luck I hope this all helps.