Hello again Scotty,

About 7 months ago I asked for your thoughts regarding OBDII O2 codes for my sons Toyota Avalon. After hearing your thoughts and checking everything I could think of, I never was able to resolve the issue. The only thing I hadn't tried to date was to replace the PCM.

However, my son's Avalon has now developed a new problem. It turns over but doesn't start. Energy is reaching the spark plugs and I can hear compression. What I don't see/hear, is the fuel pump when I turn the ignition switch. I've just started investigating, so there are some basic things I have to inspect, such as the fuses and relays. Additionally, the fuel filter appears to be the original, so that's definitely the first item I'll be replacing after 190k miles, lol. However, thinking back to issue with the O2 sensor codes in combination to this new problem, I notice the OBDII codes for the O2 sensors are no longer present, and there are now multiple misfire codes in their place.

Could the previous O2 sensor codes be a symptom of a failing fuel pump or clogged fuel filter due to the restricted fuel supply?

Comments (2)
No. 1-2
Randy
Randy

Ok. So here’s where we’re at now. New fuel pump, sock, and filter installed. I did notice a few metal particles stuck on the outside of the sock inside the tank, so I stuck a rare Earth magnet on the end of a welding rod and went all over the inside of the tank to get as much out as possible until I couldn’t find any more with a flashlight. I’m assuming they were from gas station pumps. Anyhow, got the car started but it’s running really rough now. I did watch your other video with a Toyota on how to clean the air intake. I’m going to do that this weekend, weather permitting. However, could the rough running be the result of the misfires that had been occurring for about two weeks due to the fuel restriction or bad pump? I had put new spark plugs in it only about 8 months ago.

ScottyKilmer
ScottyKilmer

Editor

pcms rarely go bad on toyotas, period. And yes, those codes could be from a weak pump or filter, pressure test that to find out