I have a 1995 Dakota with the 5.2. My bi-annual smog check is coming up, and I have had issues in the past. The EGR "works" meaning the valve lifts during cruise and even during the smog test, but it does not lift enough. At most the BPT sends 5psi of vacuum to the EGR, never more, even if manifold vacuum is much higher. The last time I did a smog check 2 years ago I worked with the smog tech and we figured out that the truck passes smog if the EGR gets 8psi or more of vacuum. At 5psi the nox is still too high. I have the FSM, but it's not clear on the details of how the BPT works and what might increase vacuum to the EGR.

Any ideas? Is 5psi normal for the EGR to receive? I'm wondering if either the BPT or the EGR is faulty. I don't like replacing parts without being fairly confident it will fix the problem.

Thanks!