Well, one week and 400 miles into my "new" car ('02 Blazer), there goes the check engine light, and a slight intermittent shudder at the idle.

Luckily it's well within the token 2 month/2,000 mi warranty, so of course I intend to pursue that, but if it turns out that I've been screwed, I hardly trust their mechanic to tell me so...

Which brings me to my question, since this thing is 10 years younger than any other car I've ever laid hands on...

Can you still read ECM codes on a Chevy by finding the two terminals near the fuse pannel and bridging them to read the blips on the check engine light, or do you need one of those pricey little trouble shooting computers that I've heard complained about?

I suppose it'll tell me that when I buy the manual I'll need to find out what the trouble codes are, but no sense buying the manual if I can't do that.

I read the other day that if the check engine light comes on and nothing seriously seems to be wrong it is often the seal around the gas cap. Once you lose pressure in the tank the light comes on.

It may not help one bit but I thought i'd toss that out there. Hell, it might just work.

Well, I went and bought the manual before I noticed the replies here... no big deal because I'm sure I'll eventually need it.

And unfortunately you're right... don't bridge anything. I really miss the OBD-I (I've never owned anything newer than '94 before, so I've always been able to just run a wire between two terminals and count the blinks of the check engine light- I wasn't even entirely certain that this was impossible on OBD-II until I checked into it).

I'll have to invest in the scanner soon- 250 bucks seems worth it to keep the gas mileage good. Preventing the loss of 1 MPG to a bad sensor or other problem would save me 6% on fuel if I've done the math right, meaning that the scanner will pay for itself within 2,000 miles of the first problem that costs me gas mileage.

To my delight though, the dealership isn't giving me any flak about actually using the 2,000 mile token warranty that they offer (I just naturally assumed that there'd be fine print specifying that it only covers a piston protruding through my hood), so this one is on them, giving me a little time before I have to spend 250 bucks (a small fortune to a college student who has elected not to take student loans until transfering to a 4 year school).

Thanks for the replies.

(edit to add- I've lost 2mpg it appears, and I'm still noticing a slight shake at the idle, so I doubt gas cap and dip stick. Timing came to mind, but someone a little more experienced than me says that while that makes sense for my usual cars, it seems unlikely for a newer one.)

[edit on 9-1-2007 by The Vagabond]

Thank You for the AutoZone plug..........

pep boys has a mini obd2 scanner you can buy for $40 that will tell you what set the light off.

Not specifically related to your problem, but you should consider making friends with one of the technicians.

Once you're buddies with them, many techs will work for cheap on their own time. Cheap = beer. Most dealerships have shop nights once a month where techs can work on their own cars and that of their 'families'.

A case of beer is a small price to pay to get hooked up to the diagnostic machines.

If you live in California,Auto Zone can no longer do a code scan on your car,another way we are screwed,evidently it stops the mechanics from ripping you off for using the same scan tool,you can buy one for around 70 bucks,worthwhile investment if you work on your own car

Well, I've been dealing with this problem intermitently for a year and a half, so the thread is back.

Go figure, the dealer blamed the gas cap and replaced it, and cleared the trouble codes while they were at it, getting rid of the light. It ran fine for a while (the shudder was very mild and went away not long after the gas cap was replaced) then the shudder came back much much worse about 6 to 8 months ago.

I went to autozone, checked the codes, and found a random misfire on multiple cylinders. I filled it up and put in some techron, then limped it up the freeway to my dad's house to change the plugs, and the distributor cap and rotor. The techron and full gas tank fixed the problem before I got to my dad's, (it had gotten to the point where i couldn't put my foot into it or idle it without stalling, and it went away completely) but I changed the plugs, cap, and rotor anyway.

Recently phase III has started. When low on gas (but before the low fuel light comes on) it is extremely difficult to start the engine. I often have to put it on a battery charger to turn it over enough to start it. Filling the gas tank always fixes the problem. A new fuel filter didn't change anything.

So it seems like a slam dunk to me that I've got some crap in the bottom of my gas tank and probably on my fuel injectors too.

Cleaning the injectors is no problem. But the gas tank is outside my experience. Am I going to have to drop the tank to check this out, or is there an easier to access point somewhere that would definitely trap contaminants and let me know whether or not there is a problem in the tank?

Thanks for the tip. New injectors just aren't in the budget right now. First item on the agenda is to clean them up and hope they are only obstructed.

If the injectors are leaking, I should be able to turn the key off and on repeatedly and then smell it flooding for a quick test, correct?

Thanks for the tip. I'll let you know how it plays out when I finally get it done. (I am the master procrastinator, as evidenced by the start date of this thread).

i feel for ya man. lotsa trouble dealing with auto's sometimes.

this is just my opinion but i would never take my car to autozone to have them read the codes. i don't even let em put wiper blades on

I've never had a problem with autozone helping me read the trouble codes. Mostly I just do it because having one of them come out to the parkinglot with me is a lot easier than leaving a 200 dollar deposit for the reader. Having seen the test autozone gives applicants, I wouldn't trust them to be the final word on something tricky, but for most intents and purposes, if you also have a decent idea of what you're up to, there's not too much danger of you and them together screwing up too badly.

my car threw a code yesterday while i was driving. car was stuttering and i had to pop in it neutral at a stop light to keep it from stalling. i got to where i was going and shut it off. did what i had to do and when i got back in everything was fine. no light and no running problems.

must not have been a hard code