Passing emissions test

Moved to Cleveland, and have to pass a sniff test looks like. Besides seafoam, plugs, spark plug wires, Shell and an oil change any ideas how to ensure I pass emissions.

Got new fuel injectors as well.

No illuminated CEL on dash.
No stored errorcodes related to engine/fuel system/ignition
No exhaust leaks between head and cat.
All emissions related systems working.

I would also check all the vacuum lines around the intake. That's what caused my problems surrounding emissions testing.

Pressure heat hose installed and intact, ignition timing on, EGR clean and operational.

What car?

yeah the car matters.....

86? or 87? 765T M46?
Do they do a thorough visual?
Dyno rollers or just idling? 15 and 25mph acceleration test, or just idling and fast idling for a minute or something easy?
Numbers you have to make? CO, NOX and HC or just HC and CO?
Gas tank pressure test or no?
Safety inspection or no? (lights, brakes, serious rust)?

Ignition timing? Set it as retarded as is permissible to make #s if they check...set it advanced just far enough ti doesn't ping on the fuel you usually burn (I don't like having to know anything special and always aim for regular/cheap/bad gas on DDs)
All injectors spray the same?
No vac/air leaks?
Spark plugs all a nice shade of tan/pink evenly?
Got a cheap harbor freight temp gun to check that the outlet temp of the cat is warmer than inlet?
Has decent even compression numbers and doesn't burn much oil?
Valves adjusted to the looser end of spec and cam not worn?


Just clean oil and a good tune up, no air leaks, ignition a little retarded and good and hot usually works. Stick shift cars you hope the test tech doesn't crunch the gears or drive them in such a way that it really revs them up and stirs up all the hydrocarbon filled oil in the crankcase and run them at light load/higher revs where they might fail NOX. Automatic cars pass dyno tests easier most of the time.

Good luck.