I live in CA and have a 1994 4Runner SR5 with just over 200k miles

when i first went to get it smogged i failed the NOx part of it
heres how i failed

Results on 6/3/14
NOx
15mph MAX: 356 - AVE:39 - MEAS: 552 = FAIL
25mph MAX: 533 - AVE:57 - MEAS: 521 = PASS (barely)

after reading a bunch of forums, i tried fixing the solution myself and was successful in doing so. Heres what I did:

1. Took of my EGR Valve and soaked it in carb cleaner for a couple of minutes (do not soak anything electrical), drained/dried it out and put it back on.

2. Put some LUCAS FUEL SYSTEM CLEANER in my gas tank along with some 91 OCTANE.

3. Put about 3/4 of SEAFOAM in my oil and the rest of the SEAFOAM in a container and slowly sucked it up the vacuum hose using 10 second intervals to insure your engine does not stall or plugs dont foul, turned my truck off for 5 minutes, started it back up and watched all the nasty smoke come out of my tailpipe.

After doing these 3 steps i took it out for a drive, opened it up on the freeway, and noticed a HUUUUGE difference.
My truck idles better, accelerates better without surges, and doesnt smell like a city bus anymore!

Final results 6/21/14
NOx
15mph MAX: 356 - AVE:39 - MEAS: 80 = PASS
25mph MAX: 533 - AVE:57 - MEAS: 75 = PASS

So if you ask me, SEAFOAM is the BEST!

overall better performance & lower emissions

 

Yea Seafoam is like aspirin for these old trucks. If you need something stronger for the I take cleaner GM makes some stuff that worked on my Chevy to get rid of the valve tick that all the 5.3ltr seem to have. Ran 3 cans of Seafoam through it no change. One bottle of the GM stuff awesome. When I get a chance I will post the part number if anybody is interested.