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Discussion Starter #1 (Edited)
New member here. My future son-in-law has a beat up 96 3.9L Dakota.
Standard Trans. It failed the smog test due to High Nox.

everything else passed. Note that NOX was low at 15 mph

Test Results:
15 mph: 1473 RPM, CO2-15.05, O2-.16, HC-63, CO-.41, NO-0036

25 MPH: 1488 RPM, C02-15, O2-.47, HC-43, CO-.02, NO-1360 FAIL (MAX ALLOW - 859)

186K miles on it.

He has had the truck a couple of years. He "thinks" he put a new CAT on it when he bought it.

I figured it might be the EGR valve, but I've since learned this year doesn't have one (please confirm)

I smell fuel/gas under the hood when it's running, not real strong, but it's there.
There are no stored OBD error codes.

Seems to idle ok, maybe a little rough.
I volunteered to try and help him out, so now the truck is at my house!

Other than look for the EGR that doesn't exist, looking for codes, and smelling the fuel, I haven't done anything.

I know to look for vacuum leaks and I'll do that, but in the mean time I thought I would look to the wisdom of the forum.

Anyone else have this issue?
Anyone have any suggestions?
Please don't let it be the CAT

Thanks in advance
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