2-Stoke Fuel in my Tacoma. Now I've got a p0420 code

Maintenance/Repairs
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21

An oscilloscope is simply a device that turns electrical signals into graphic presentations. Those heart things that you see on doctor shows that show the heartbeat are oscilloscopes. O-scopes are used to do many things, including measuring the time and frequency of signals, voltages, currents, temperatures, pressures, and anything that can be detected by a sensor and converted to an electrical signal. They can do far, far more, including comparing signals, freezing scans (modern scopes), etc., but you get the idea.

When someone uses an O-scope in automotive diagnosis they’re just measuring signals. The signals can be used to determine exactly what signals the sensor(s) on the engine are sending to the ECU and/or what signals the ECU is sending back to the engine’s controls (throttle motor, injectors, ignition, tranny commands, or whatever’s relevant to the diagnosis).

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The most user friendly scope that I have ever used was this Snap-On

https://www.snapon.com/diagnostics/us/vantagepro

A 4 channel lab scope can be more accurate and informative but it has a very steep learning curve.

23

I haven’t been here for a while but figured I’d give an update. The truck is not a V6, it’s probably as small as you get with a Tacoma. I’ve probably driven over 200 miles maybe even 300 after today and the light still hasn’t come on. I’m wondering if maybe it fixed itself if that’s even possible.

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If a problem is detected and a code is stored in memory but the problem doesn’t persist, after some number of drives the CEL turns off. The code may also be erased. Details vary by carmaker/model/year.

Thanks for the update and good luck going forward.

25

Alright I know it’s been quite a while, but I figured I’d bring another update to the page. Basically my truck every once in a while turns on the Check Engine Light, but it turns itself off again quickly for a while. So I’m thinking that maybe the oil in the mixed fuel made a little bit of a difference but all in all not too big a deal. However, unless someone was able to show me some serious science on why it doesn’t matter, or unless it’s in the case of an emergency, I probably won’t be doing it again because it seems logical to me that there is always the potential of it causing unnecessary problems with the CAT.

Thank you to everyone else who ever contributed to this thread.

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I think that’s wise decision making. Better to not take the risk.

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So I shouldn’t put top oil in every other tank anymore? That is what we did in 1956 with our 41 Studebaker.

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You should continue to do this on all of your '41 Studebakers. :grin: