Premature EGR failure 2.5L V6

My 1997 2.5L V6 Dodge Avenger (same power plant as the Sebring) keeps
damaging the EGR valve. The car will run smoothly for 6 weeks after
installing a new EGR, but gets steadily worse from there. I'm on my
third EGR valve right now. The damaged EGR valves have lots of black,
sooty deposits in them.

The car does seem to have less power these days even when it is running
smoothly. I am using the OEM EGR and solenoid parts bought directly from
the dealer.

I've tried the following to fix the problem:

Had the car checked out by a dodge dealer's shop (they found _nothing_
wrong.) They checked for vacuum leaks, bad air/fuel mixture, etc.
According to the dealer, there are no TSBs about this problem.

Took the intake plenum, EGR inlet pipe, and throttle body assemblies off
and cleaned away all residual carbon. Replaced all gaskets for those
parts.

Had the fuel injectors cleaned.

Replaced the spark plugs, replaced spark plugs wires. Dis cap looks
great.

Had the catalytic converter pressure tested (18 psi). The guy at the
exhaust shop told me that was a little high but still acceptable. Don't
know if that's true.

Replaced the upstream O2 sensor.


The car has 90,000 miles and uses no oil. Otherwise, it's a great car.
Please help me find this problem!

 

With what brand? If you used Bosch, you've got better-than-even odds of
needing another new O2 sensor. Use an Echlin, NTK or Mopar sensor, NEVER a
Bosch.

 

[snip]

If you're describing an exhaust back pressure measurement ahead
of the convertor, 18PSI is way too high. Three PSI is the
defacto industry standard for maximum exhaust back pressure.

 

What are your symptoms to make you think it was the ERG valve?

-Tom

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