Super rich condition... Codes inside
 

My father-in-law's 92 has had a recurring problem with a rough idle and rich condition while at idle.

Fuel pressure has been checked. We have tried both 38 psi and 40. The condition exists with both settings.

Timing is set at 14 degrees.

No vacuum leaks present.

O2 sensors are less than a year old.

KOEO codes show:
34 (EGR)
KOEO codes show:
34 (EGR)
The rest are kind of vague, but we seem to be getting an O2 sensor code (rich/lean condition) occasionly. The codes are kind of hard to make out. We have the tone type reader.

Could the EGR valve cause such a rich condion? I know it can cause a rough idle for sure.

If you stand behind the tailpipes, it will burn your eyes from the fumes. The car runs great when you get into the throttle.

Any ideas before we start replacing parts?

The EGR would cause a lean condition, which the ECM would try to correct by richening the mix. I would fix what you know is wrong first, and go from there.

:)

Thanks for the help Chris. We are replacing the EGR and the EGR position sensor right now. Hopefully it will help.

Good luck.

:)

Update
 

We changed out the EGR valve and the EGR valve position sensor. We cleared out the stored codes in the computer and then ran another KOEO test. The only code we got was:

34 EVP/PFE High

We used a OTC4000E code reader. We have yet to run a KOER test because his tach is stuck at 3000 rpm for some reason. This would make it hard to keep it at 2000 rpm for the KOER test.

The car still runs great except for the rough idle and rich mixture at idle. Any ideas?

Clean the wiring
 

I would clean the wiring connections on the wiring harness. I would then put some dielectric grease. Make sure you clean the connections to the ECM also.

Thanks for the advice, but that does not explain the reoccuring code 34 KOEO that we are getting. We will check the ECM connections although it has never been unplugged since the car was new.

My experience
 

I had a reoccuring MAP Sensor code on my 89 Vert. The Map sensor was brand new. I did the tests that the Ford Fuel Injection book recommended. The tests came up with poor results saying to replace the Map. I new the MAP was brand new. I cleaned pin connector to the ECM and the MAP sensor worked perfectly.

I would think about this since you have a brand new EGR and valve. I think it would be worth your time and money.

Cool, it's worth a shot. Thanks.