Hi-
So I failed smog today. I came home and spent about 3 hours on the internet (2 of those on yotatech, my new favorite addiction), and am about to reach some conclusions- I was hoping you folks could steer me in the right direction, correct me where I'm wrong, maybe see some pattern that I'm not seeing in the readings. TIA

Just bought a 1990 4runner, v6 3.0, auto. Bought it as-is, which I know isn't that wise but I got it for a lark.

Results from smog:
At 15mph, 1765 rpm,
%co2-13.5
%o2-1.5
HCppm- 34 (ave 35,max118)
CO%- 0.83 (ave 0.11,max 0.68)
NOppm- 368 (ave332,max999)

At 25mph, 1772rpm,
%co2-12.9
%o2-1.6
HC-78 (ave 24, max 98)
CO-1.57 (ave0.09,max0.87)
NO-789 (ave 274, max859)

Failed CO both runs, but HC and NO were within range, although NO and HC jumped at 25mph.

So, here's what I've gathered from my research- my fuel is running rich. The high CO levels probably come from the cat and/or the o2 sensor needing replacement. I've also found a number of tricks to help increase the odds of passing, but my CO levels seem a bit higher than what a couple of tricks might improve.

But, get this- Today I had a tune-up and a cracked vacuum hose replaced, then went directly to smog right down the street and failed. Afterward, in my quest to pass smog, my first step was to get an oil change (and flushed cooling system and brake fluid for the heck of it). Actually that was my last step bc I'm not quite positive where to go from here.

Should I have run the truck up and down the freeway for a while to let the cat get warm and for the system to get used to the replaced hose (?I'm guessing at that)?

Also, if my fuel sensor is right, I'm getting horrible gas mileage- if this keeps up I'll be lucky to get 120 miles this tank. Oh curses, that might be what 4runners get, huh? :/

I'm thinking of two choices, one cheaper than the other:
1- I can run through a tank of gas, add some of that special additive that I would find at my local auto parts store, add more gas (and some methyl alcohol?), get the truck good and hot, drive her into the parking lot, let her rev some more, and then let them test her.... or....

2- replace cat and o2 sensor and live off of Top Ramen and KoolAid for the rest of the month..


Please let me know if I should clarify anything. Thanks for your patience and advice in advance!

 

forgot to mention-- car has 228k miles and i guess before i bought it the cel was on. previous owner took out air filter, vacuumed it out, and cel turned off. Had my mechanic run the code when he did the tune up and it came back something about thea/c switch. Wasn't so worried bc there's no a/c belt on it right now and a/c isn't a priority- but could all that be related?

 

Mods- Should I have posted this somewhere else?