91 V6 CQMRY Question

Not sure if stuck open EGR would be a case! Have you cleaned Throttle and IAC valve?

If the EGR is stuck open, you will get cold-starting difficulty. During cold-staring the engine management is in closed loop mode. This means the exhaust is not being sensed for correct mixture and as the EGR is admitting too much exhaust, the intake is too lean.

It's a chicken and egg thing ie exhaust gas recirculation goes on the fritz first,.. causing hard starting second.

The poor emmision test probably means the EGR is not putting putting in enough exhaust once the engine has heated up. So I would expect the EGR is stuck 1/2 open, giving too much when cold and too littel when hot.

Jason

The EGR valve was replaced today; it passed the NOX emmission test, but failed the CO2 test. Am told that the catalytic converter has failed due to the EGR valve failure ! ?

Is it possible that a failed EGR valve will cause failure of a cat converter ?

The cold start difficulty disappeared about a month or two ago.

This has not been a very good month !

Not an expert on cat-convertors, but I fail to see how the small amount of exhaust admitted into the intake could do *anything* to the thing.

It must have failed due long service.

Jason