Good day guys, just last night my upper rad hose blew and I noticed the car overheated, idk how long it was like that but it wasnt for more than maybe a few minutes. Repaired the leak and fixed the overheating issue, now today I have a p0170 & p0171 code. Never had this code before prior, could be a coincidence or it was related to the overheating, not sure. I have a basic code reader with some basic live data readings, Short term fuel trim at idle in closed loop keeps increasing to 40-50%, it decreases down to low single digit numbers when I accelerate. O2 up/downstream has been replaced back in 2022, I didnt find any obvious vacuum leaks at all. Full tank of 91 gas as well. MPG has decreased significantly compared to my last fill up which went 270 miles. I am barely hitting 33 miles on this current tank and i am 1/8 of the tank used up already. Any insight would be helpful, I dont know if I should condemn the upstream 02, I also have on order a new fuel pressure regulator.

Symptoms currently are a slightly rough idle, when I am driving and accelerate, sometimes it almost feels like the transmission is slipping where there is nothing happening and then all of a sudden the transmission grabs and launches the car forward again.

Car is a 1998 Accord 3.0L V6

 

Bump anyone?

 

UPDATE: I hooked up a different scan tool to read live data and during my test drive the check engine light turned off on its own, my fuel trims and O2 voltage readings look normal. Car still drives fantastic without issue. BUT every once in a while when it was safe to do so I looked at my live data and saw my O2 sensors up&down stopped switching in voltage and stayed at 1.275/0volts and my fuel trim spikes up to 43%. I start driving again or give it some gas and it goes back to reading normally. Weird stuff happening

 

What you are most likely observing is the fuel cutting off during light load/deceleration. This happens when closing throttle or engine braking.