rjryowit

New member here. Failed CA smog at low speed. Had local shop who has serviced car for many years look at it. He says no vacuum leaks, cat looks good, but needed plug change.
Went back in today, failed again. Actually little worse score.

Here are my measured results from todays test.
15mph
%co2 14.60
%o2 .02
HC 90 max is 58 (first test 84)
CO .25
NO 0348

25mph
%co2 14.78
%o2 .00
HC 48 max is 48 (first test 48)
CO .08
NO 0085

Any ideas of what to do? All previous smogs I have always passed with room to spare. btw have 235k miles on it.

DixonPai

iTrader: (3)

Did they let the car warm up before going in to test?

rjryowit

Yes. I drove it for 30 minutes plus they let it run about 15 minutes before they tested.

Mxkmster

Tune ups are a super big deal on these cars. Got to make sure everything is good. Spark plug wires, spark plugs, distribtor cap, pcv valve, and clean and make sure your EGR is working. do you have a picture of your printout from smog

lexus4all

Don't know if the situation has improved, but drive the car until almost empty. Then put in some fuel injector cleaner (Preferably Chevron with Techron). Drive around a bit more and then fuel up with quality gas.

After that, clean your air filter and try again

DGIKULJOT

My car which is a 98 Lexus Es300 kept failing smog too. One shop I took it to claimed nothing was wrong except the ecu. I let my neighbors relatives work on it since I was really busy with school at the time. They changed a bunch of stuff such as the intake gasket, MAF (even tho it tested fine for me), intake air temperature sensor and one of the AFR sensors. After that it passed with flying colors. The intake gasket wasn't even obvious so I would look at all that. Especially the Intake temp sensor, if it is bad the car will put in incorrect amounts of fuel thinking the air is colder then it might actually be and such. The AFR sensors are another biggie.