So my 94 fleetwood won't pass smog due to high NOX.

My fathers a mechanic and he's been helping me out. We checked the EGR Valve and it works...solenoid works...and even tried and tested a new PCM on it...

So my question is has anybody run into the problem where the scanner does not read the EGR...all my sensors are working but while sitting on idle it misses a bit. We even drove the car with the Valve tester on an no pressure is showing from EGR, and its nor reading it on the scanner? :hmm:

I even bought a new EGR valve..but still does not read on the scanner..

What am I missing or what options left do I have :nono:

I've even had a friend that works at a cadillac dealership take a look at it and he's confused too..he went through his whole checklist but his last option is to replace the PCM... but I already did that once.

have you changed the opti spark dist cap????

no? why may I ask

From what I know about the 94 Fleetwood, I believe it used a computer controlled vacuum regulator, which controlled the EGR valve. If I'm correct and that is how your engine is set up, then you should replace the vacuum lines running from the regulator to the EGR, test the regulator, and then test the wiring harness and connector to the regulator.

The fact that your PCM does not read the EGR suggest that it is a problem with the vacuum regulator or regulator control circuit.

I will look into that...that might be the solution...Its just that when I hook up the scanner to it...it shows that there is no pressure to the egr...that makes sense though..will look into it thanks.