I'm giving a 2-3 month history in case any problems might be related.
Some of the history, of course, might be irrelevant.
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2001 Chevy S-10 Blazer, 4-door, LT, 4.3L V6

mid-May 2010: Tune-up. New spark plugs, rotor, cap, and wires.

Symptom: ABS and BRAKE lights are on -- sometimes.
Start date: Within 7 days of tune-up.
Observations: Intermittently, the Blazer's ABS and BRAKE lights will
turn on. Sometimes, they will not be on when we start
the car. Sometimes they come on at startup, and sometimes they come on
while driving. They have not ever cleared while driving.
Possible diagnosis: ABS module needs to be sent to Idaho to be reprogrammed.
Possible diagnosis: Problem with wires from tune-up?

Symptom: Loud whirring noise (wah wah wah wah wah) from driver's side
of car. Went away on right turns.
Start date: ~10 days from tune-up
Diagnosis: Bad wheel bearing hub assembly, drivers' side.
Outcome: Replaced drivers' wheel-bearing hub assembly, symptoms ceased.

Early June 2010: (one-time event) Car hitches when changing gear and
going uphill, CEL comes on/stays on.
Assumed it was a misfire and a spark plug/O2 sensor threw the code and
that it might go away. It didn't.

Symptom: Blazer stalls at low fuel when accelerating.
Start Date: End of June 2010.
Observations: Several times when near 1/4 tank or lower, the Blazer
has stalled. Each time, this has been from a stopped position (say at
a red light) and while pressing the accelerator (i.e., we try to go when the light turns green, and we get about 10 feet before we stall and have to pray that the guy texting in the car behind us doesn't rear-end us). Filling the tank
alleviates symptoms. We kept it above 1/2 tank and had no problems for
about a month. Then on a long trip we dipped below 1/4 tank, and when
we exited to get gas, it stalled on acceleration at the first (and
only, thank goodness) red light.
Possible diagnoses: Fuel filter, EGR Valve/Gasket needs to be
cleaned/replaced, Throttle Body needs to be cleaned, Ignition Switch

Symptom: Blazer sounds noisy, like a motorcycle.
Diagnosis: Exhaust Leak; Needs part 10217106 connecting the check
valve to the line (A.I.R. system, #16 on the exploding diagram).
Side Effects: Exhaust melted a (large) hole in the Air Filter Housing,
has not damaged the filter. Will have to get a used one from a scrapyard.
Question: Is the air filter housing (bottom half) easy to remove/reinstall yourself?
Question: How much should I be paying for this part from a scrapyard?

While looking for part 10217106, I had autozone dump my CEL codes, and
I have two codes, both P1406 according to the AutoZone man. So, I'm
now operating under the assumptions that my stalling is EGR-related
and that my ABS is wires or module-related. I'll change the fuel
filter for good measure.

Thoughts on the above? My diagnoses are basically from scouring the forum.

Thanks in advance,
bkw

Follow-up:
We've also noticed that sometimes the a/c fan isn't blowing very well. This is atypical and usually happens on really hot days or when the car is working really hard (e.g., through the mountains). The air is always the appropriate temperature; it just doesn't blow.

 

P1406 - EGR Valve Pintle Position Circuit

The most likely cause of that code is the valve itself, but clean the valve and check the wiring to/from the PCM first. The valve is expensive.

As far as your abs light, get the ABS codes scanned (not an autozone thing) and report back with the code(s).

As far as your stalling below a 1/4 tank, not to scare you, but that sounds more like a weak pump than it does any of the other things you have described. An EGR problem should manifest itself regardless of fuel level.

 

1. Any idea of a good place to go get the ABS codes scanned? Or is this something I'm gonna have to shell out $X to the local mechanic for?

1a. How much should $X be, approximately?

2. Hopefully my fuel filter will be all gunked up and replacing it will do the trick, then. If not, is there a FAQ/guide to testing the fuel pump? I'm trying to do most of the work on the truck (unless I'm totally over my head), but I'm still learning, for sure.

Thanks for your help. I feel like I owe you a beer for all of your posts I've read over the last several months.

 

You are going to have to find someone with a full feature scan tool to access the ABS control module. Shops typically charge 1hr to do 5 minutes worth of work to pull the codes. Rates vary. I doubt you will find someplace that will do it for free.

There is a wealth of information in the Tech Article (DIY) section. Have a look at the index link in my signature.

 

You are the man. Thanks again. Will update once I play a bit. Oh, sorry one more thing. Will the P1406 go away by itself, or do I have to get someone to clear it and see if it comes back (and if the latter, is that an Autozone thing?)?

 

You can either wait, get it cleared, or pull the battery connection. If you fix the problem, it will go away on its own.

 

Quick update: Life gets in the way of toying with the car.

But I cleaned the EGR valve by leaving it in an inch or so of carb cleaner overnight, and spraying it down on both the valve and the car side and brushing it with an old toothbrush. Replaced the gasket with a new one with the mesh filter.

CEL cleared within two days of mild driving.

Also, air filter housing was replaced, and the plastic elbow was returned to my exhaust system, but there is still a "sputtering" or exhaust leak sound. So next up is diagnosing the leak and I still have to change the fuel filter / check the fuel pump pressure per the above stalling discussion.

 

Defeated

I've spent the last 2 hours trying to get this damn fuel filter off. I definitely can't turn the nut, and I can't even get the QC clip off, even holding the plastic tabs with a pair of needlenose pliers.

I'm sure this would be infinitely easier on a hoist, so -- even though I really wanted to DIY -- I think I'll have that done in the AM (probably to the tune of ~ $50 )

 

ABS code is a C0265 EBCM relay.

 

Trouble code diagnostic sheet:
C0265/C0266 - EBCM Motor Relay Circuit

And a quick search for 'C0265' to see what other members have done to remedy this code.