Fuel System/Emissions
Sensors (O₂, or oxygen, sensor), emission-control devices (includes EGR), fuel-injection system, fuel gauge/sender, fuel pump, problems filling up the tank.
What Owners Say
"carbon build up. Engine surges or dies down"
Anonymous, CA (2003 Toyota Avalon XLS 3.0-L V6)""The oxygen sensor that went bad, is screwed into the catalytic converter. They need to come up with an easier way to be able to connect and disconnect this part. It is like taking a rusty bolt out of an exaust system, and the sensor wire requires over an hour to snake into the engine compartment. once fixed you are set. DO NOT use anything but a DENSO Toyota OEM on their 02 sensor replacements, everything else out there is pure junk for this task. The denso works perfect.""
Anonymous A., VA (2003 Toyota Avalon XLS 3.0-L V6)
""The EGR related issue was a little magnetic valve that integrates with the throttle body. It sits on the top. It can get gobbed up with gunk and cause the check engine light to come on, between that and the oxygen sensor, these are the only things that have given me any trouble and I have been driving it for 8 years. once I got the oxygen sensor fixed and that little valve at the top of the throttle body cleaned and moving right, everything has been going fine. They need to find an easier route for the wiring to go from that oxygen sensor that connects with the catlytic converter, and a better way to connect them together. that oxygen sensor practically fuses itself with the catalytic coverter, and you have to be tremendously careful not to strip the threads in the cat converter where that o2 sensor hooks in. The cable back to the computer goes on a weird journey from just under the passenger seat up to the firewall and through a hole in the firewall. they could find a shorter route that would run totally under the car into the engine compartment, I am sure. The Avalon is an incredible car. Quiet, fast, and plenty of headroom for a 6'3" 300 pounder, like me. Would I buy one again. In a heartbeat. This is one of the best engineered cars I have ever driven.""
Anonymous A., VA (2003 Toyota Avalon XLS 3.0-L V6)