The 443 code is interpreted as a bad CAT Converter but there are several things to check first. A bad vacuum hose is the most common cause. Look around the engine for a leaking vacuum hose or two. After 10 years it wouldn't be a surprise to have one. Any exhaust leaks? Here's a summary of the shop manual troubleshooting guide. No loose sparkplugs?

Mike



Code 4-4-3 (TWC Efficiency)

1) Check for other codes. If any code for misfiring is stored
(Codes 4-5-1, 4-5-2, 4-5-3, 4-5-4, 4-5-5, 5-4-2, 5-4-3, 5-5-1, 5-5-2,
5-5-3, 5-5-4, 5-5-5, 5-4-4 or 5-4-5) perform that testing first. If
Codes 4-3-5 or 4-3-6 are stored, perform testing for that code first.
If none of the above codes are stored, go to next step.

2) Perform a compression check on all cylinders. Repair as
necessary. If compression is okay, go to next step.

3) Check for air leakage in intake system. Repair as
necessary. If there is no air leakage in intake system, check for air
leakage in exhaust system. Repair as necessary. If there is no air
leakage in exhaust system, check fuel and residual pressure. Repair as
necessary. If fuel and residual pressure are okay, retest using new
TWC.

Reset it and see if it goes away. Can be caused by bad front O2 sensor, bad cat, exhuast leak or intake leak. The O2 sensor and intake leaks will usually throw thier own codes too but not always.