Me again, asking for free mechanical advice . . .

[BoSoxGal]

So yesterday I get in my car at lunchtime to go pick up some nasty tacos and BING! my 'check engine' light is on. Car is running funny, spitting and sputtering like it might stall out.

I pull over and check under the hood, to see if my plugs have come loose (when I replaced the original plugs and wires in '09 with after market ones, they kept popping off for months until I finally broke down and bought a Toyota made set).

Nothing under the hood looks amiss, but the muffler sounds funny.

"Damn!", I think. I was just talking about how I've got a low mileage (relatively speaking) Toyota that I'm going to run into the ground. Now I've got to enter the scary realm of auto mechanics, for a not obvious problem. That's a sinkhole for cash, right there.

So, after work I go out and start her up and she's back to running normal/fine. Same thing this morning. The check engine light is on still, but I know from past experience (when I had to have an O2 sensor replaced) that once the computer triggers the light, it has to be manually re-set.

Any ideas, automotive mavins?

[liberty]

I have had no experience with it I have only heard of it and seen it on TV, but have you considered purchasing a “Car Doctor “system?

[dales]

Go to a "trusted shop" and have them "pull the codes".

I had the dammed O2 sensor replaced last year after my car ran worse and worse.

Runs like a champ now.

[Liberty1]

I would suggest buying a code reader, I got one a couple of years ago from Costco for about $30, I think you should be able to get one for $50 or so.

They are easy to use, there is a connector right under the dash it plugs into. You can read the codes, which gives you the information the shops will have, beforehand. You can clear the codes if it is now running fine and see if they come back. Well worth the money just to have the "secret information" the shops may or may not tell you.

[Gob]

Our Subaru has had the "check engine" light flash on at least once a day since we bought it. We ignore it.

[BoSoxGal]

I'm considering that approach. She's running beautiful again today, so why stress?

My rule of thumb; if it ain't acting broke, don't go broke letting the mechanic find a zillion things to 'fix'.

[BoSoxGal]

Go to a "trusted shop"

You're kidding, right?

[BoSoxGal]

I would suggest buying a code reader, I got one a couple of years ago from Costco for about $30, I think you should be able to get one for $50 or so.

They are easy to use, there is a connector right under the dash it plugs into. You can read the codes, which gives you the information the shops will have, beforehand. You can clear the codes if it is now running fine and see if they come back. Well worth the money just to have the "secret information" the shops may or may not tell you.

Seriously?!? I had NO IDEA I could buy such a thing! Thanks, I'm off to look for one this very minute.

[Guinevere]

Many auto parts stores have code readers you can borrow (for free) too.

Even if its running well, be warned, if it throws a code and its not cleared, it can muck up your annual inspection -- if you're unlucky enough to live in a state that requires such things.

And yes, I have a very trusted mechanic -- they do exist -- ask around!

[BoSoxGal]

No inspection in Montana - yay!

[Sean]

Maybe the 'check engine' light is broken...

Isn't there a 'check engine light' light?*


*Thanks to Dr Sheldon Cooper for that one...

[dales]

Our Subaru has had the "check engine" light flash on at least once a day since we bought it. We ignore it.

That's what I do.

My dammed C. E. Indicator comes on intermittently, I ignore it until it's CA Smog Check again.

(CARB basturds!)

[loCAtek]

When I had my old truck (which always passed) I used to cover up that light with a piece of tape.

Damn, I miss that truck...

[Jarlaxle]

Many auto parts stores have code readers you can borrow (for free) too.

Even if its running well, be warned, if it throws a code and its not cleared, it can muck up your annual inspection -- if you're unlucky enough to live in a state that requires such things.

And yes, I have a very trusted mechanic -- they do exist -- ask around!

Many auto part stores will pull codes for you, free of charge. (Auto Zone & Advance will in this area...I think C-S-K also do that.)

[dales]

Jarl is right.

[quaddriver]

fuel+air+compression (lack of gaping holes in the block) = engine runs.

gaping holes dont go away so lets assume it is intact.

therefore it was stumbling due to lack of coherent spark/timing, or fuel delivery.

The worst an O2 sensor can do is not work at all, in which case the car runs on a best guess, albeit rich, but runs

mass air or map sensor thingies when going south tell the computer that you are batshit behind the wheel and try to run the engine as it thinks you are commanding it. they therefore show up as bad ign modules or quaddrivers.

not only have the codes read (and post them, they will all be Pxxxx for this problem) but have the engine functions monitored

[BoSoxGal]

Okay, I'm going to stop into AutoZone Saturday morning and ask if they'll read the codes for me. If they will, I'll post them here.

She's running great still, so I'm thinking that a mouse was stuck in the exhaust briefly.

[dgs49]

Could be a faulty oxygen sensor, but the fact that the car was running poorly indicates that the O2 sensor might be functioning as designed. Could also be a catalytic converter.

A friend of mine has been running his Camry with the check-engine light on for about 50,000 miles (it now has about 175,000). The dealer warned him that if he didn't get the problem fixed it would shorten his engine life.

He resets it before taking it in for state inspection every year. Fortunately, his county does not require an emissions check.

[dales]

The dealer warned him that if he didn't get the problem fixed it would shorten his engine life.

Or the dealer "tech" might miss another boat payment.

[Jarlaxle]

It can...running excessively rich will hurt an engine. It can easily burn out the catalyst, and can eventually kill the compression as fuel washes the oil off the rings.

It also, of course, wastes fuel, not a good thing at $3.20/gallon.