I took my 97 F150, 5.4L in for a smog and it came back with high Co emissions, 1.02 measured vs 0.58 maximum. It also showed P0135 and P0155 codes for O2 sensor heater malfunction, or something like that. I heard that just replacing an O2 sensor will not necessarily fix the problem and keep the codes for recurring.
Any suggestions on how to repair the codes or reduce the CO?
Will octane booster help, or maybe ethanol, if it's even available in CA?

 

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They do emissions testing in El Paso as well. There is a quick lube that buys around 5-10 cases of this stuff ever month or so. It really seems to work on those that don't pass emissions

 

Fix the cause of your current codes instead of screwing around with additives.

The computer is probably compensating for the faults and no junk in a can will get around that.

Steve

 

Agreed. You cannot go around the electronic system.
The OX sensors are heated to reduce the warm up time to closed loop operation.
They must go to about 700 degrees to send info back to the computer.
Without the heaters working, the response time could be slowed making there output low.
This low output will indicate a lean condition to the computer and richen up the fuel causing the higher CO levels.
If there is no output, the computer goes to a richer fixed table (for engine protection).
Do the right thing and get the codes cleared by repair and the problem will clear.

 

I agree, however, I was wondering about whether or not replacing the sensors will actually make the codes disappear and not come back.

 

The trouble codes will have to be cleared manually, they won't go away if the problem is fixed.

If the code reads O2 sensors, then that is likely the problem so you should be fine.

Search the web for the best prices on O2 sensors, because the price can vary widely depending on where you shop.

I bought some from this place:
http://www.oxygensensorwholesale.com

Paid about $50 each.

 

The CEL light will go out after enough driving cycles, usually a week or two. The stored codes take a lot longer but will disappear eventually.

 

after replacing the o2 sensor disconnect the battery to clear the codes. you will need to drive the truck for a while to get the computer to relearn so it will pass the emission test