P-0171 & P-0300 codes

So, my 2000 with 198k and some change miles had the CEL come on. I checked the code and it was P-0171, Bank 1 too lean. I reset the code just to see if it would come back, and it did. I was wondering if I might get a bank 2 too lean code, so I left it for a week or so.

Then I started noticing that it was having trouble accelerating. It was most noticeable after I left work. There is a slight incline to get out and some days it would just barely climb the hill. It feel like the transmission is slipping. I checked the transmission fluid and it is nice and red and to the full mark. (I changed the transmission fluid about 10k miles ago.)

I rechecked the codes and now I'm getting both P-0171 and P-0300 random misfire. So, I set up Torque to graph the bank 1 probe 1 O2 sensor, the engine coolant temperature, the airflow sensor, and the fuel pressure sensor.

The fuel sensor seems to be dead. I didn't see it come off 0 the entire drive into work. The airflow sensor seems to be almost dead too. It would just come about 1 line width off of zero. At a stop light I put it in park and reved the engine to 5000 rpm and the airflow sensor just barely came up.

The engine temperature is fine, showing about 185 F.

The O2 sensor looked to be pegged at zero, but when I would take my foot off the gas, it would monetarily peg high but then return to low. So, I think the O2 sensor is actually working, but it is just reporting what it sees.

Anyway. Has anyone seen this type of issue before? It looks like I have 2 bad sensors, but I find it hard to believe that both failed at the same time. Of course, I am planning on looking at the airflow sensor, and maybe cleaning it. (I cleaned it last year.) and maybe testing it with a meter.

Not sure what I can do about the fuel pressure sensor. I'll have to look it up in the manual to see what I can do.

Do these 2 sensors share a harness or something like that that could explain both issues?

Any advice will be appreciated.

 

paid version of torque? if not, get it. The free version sucks balls compared to the paid! and what obd2 interface are you using?

this kinda sounds like a bad ECU. no sensors should be dead. see what your LTFT and STFTs say. should be above 25% if it's a true P-0171 (or 12.5 depending on if it's sensing 1 or both sides).

 

PO171 Code. Just go ahead and replace the offending O2 sensor. They are normally replaced every 100k anyways as preventive maintenance. Your really close to being due.
P0300 Code. Check your plugs and wires. Plugs are cheap, get a set of double ground and change them out.

 

p0300 coils plugs or wires
p0171 o2 sensor