This time it's just kinda weirding me out instead of making me panic. It's the same code as before (71 ERG system), but the light is intermittently on. It will be on one day and be off the next few days and then come back on for a few days. I've kinda kept quiet about it and haven't messed with it just to see what it would do on it's own. From the looks of it, the car is possessed.
When you had it apart before, did you clean out the passages that are accessible in the EGR valve and associated metal tubing?
My '95 Bronco was throwing a code that said it detected a lean condition. The Check light would randomly cycle on on some trips but not others, then it would go off on some of the trips where it came on, but not on others. It never came on a second time in the same trip.
I took a wild guess and replaced one of the O2 Sensors (I have two of them) that is before the CAT, and my problem was solved.
You did not say what year your car is, but by the description of your symptom I assume it is a pre-'96 model that has the OBD I management system. I found Autozone sells a scan tool for my Ford for $35. It is a no-frills unit, but it provides enough information to make an educated guess to fix stuff at home. I'm sure there is a model that fits your Toyota.
For a pre OBD II Toyota, you do not need a scan tool to check trouble codes, a paper clip will do.
There are 3 possible causes of a lean condition trouble code: 1) bad air flow sensor; 2) bad #1 O2 sensor; 3) leak in the intake tube between the air flow sensor and the throttle plate.
The air flow sensor (MAF) can be contaminated by some air filters that use an oil bath or are soaked in oil, an air filter that allows a lot of contaminants to pass through like some "high performance" filters, or by fumes from the PCV system.
You are being too politically correct, Ray.
It is K&N filters that could be the cause....
Why anyone would want a filter on their engine that lets MORE dirt thru is beyond me....and it can screw up a very expensive sensor to boot....
Most "high performance" modifications are not well suited for street use and have a tradeoff in either comfort or vehicle longevity.
There are 3 hoses that connect to the valve. Two on the top and one coming up from the bottom. The top two have been replaced because the ends broke off when I pulled the valve. With the bottom one going straight down I don't really see a way to make sure it is unobstructed. If I detatch all three hoses, the valve comes out once I get the clamp off.
I also cleaned out the filter in the top of the valve with an air hose.
Did you do the check where you apply vacuum to the EGR valve while the car is idling to see if the engine starts to die? If the engine does not start to die when you open the EGR, then the EGR needs cleaning or replacement.
If the engine does start to die, then look at the vacuum switching valve that is connected to the EGR.
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