Sorry -- misunderstood the purpose of your post. I've checked and the wiring looks pretty good. But I will inspect more thoroughly; it would be a shame to pay for unnecessary module repair.

Thanks for the link to MM. Just wanted to make sure, since I'd swear I'd read something on here about having to bleed the brake lines. Glad we cleared that up.

Thanks again. I ordered the AC Delco part off Amazon (which I'd never have thought of for car parts, but I will now!) and it shipped last night, only about 6 hours after I ordered it. Not too bad! I'll update once I replace the spider and reinspect the ebcm wiring.

-bkw

 

You would have to get things bled out properly if you were to replace the entire ABS pump / EBCM assembly. If just replacing the EBCM, the hydraulic portion of the system stays sealed up.

 

Swapped out the fuel rail. Car is idling way, way better, but it's still hitching/sputtering/stuttering/whatever intermittently when I drive; maybe it's a transmission problem.

Drove it for about 50 miles, and then the SES came on again.

This time, I had a p0128 (which was one of the "come-and-go" codes from before) and a p0301. Then I read something that a coolant temp sensor problem can throw a p0300
(cf. http://www.automotiveforums.com/t590...ode_p0300.html )
edit: also recall from the OP that I kind of expect this to turn into a p0300 within 50-100 miles.

So now I'm wondering if there's any way this is just a coolant temp sensor problem. As a reminder, the other come-and-go code I saw before was a p0410, seemingly unrelated.

Thoughts? ECT sensor is an easy replace, right?

edit: Possibly relevant, the Blazer seems to get to a good running temp pretty easily, and I'm getting good heat. The car is in NJ, so it's been in temps in the 20s and maybe high teens of late. I'm not great about warming it up before driving it.

 

Having read a number of threads (including the dreaded P0300 thread), I have the following list of things to test. Time's fairly limited, so any help in prioritizing is much appreciated.

Plugged EGR valve
EGR valve stuck at idle
O2 sensors
Coils/coil boots
Valve Cover Gasket
MAF sensor
ECT sensor and/or thermostat
Air intake needs cleaning?
Ignition switch module

The mechanic didn't see any vacuum leaks when he swapped out the fuel rail.

Thanks in advance. Your help is much appreciated.

edit to add to the list:
Catalytic converter
Compression test (cranking and running)
Cap (see TSB 03-06-04-041a)
Plugs again?

Note that the cap and plugs were new, but this is a new engine. There was a lot of excess fuel, and I'm thinking it's possible that the fuel fouled one or more of the plugs. This would not explain the random (and recurring) coolant sensor code, though.

 

So this is turning into my personal blog. Sorry about that.

Changed the thermostat, which was stuck open. Ok, I lied. I have a friend who owns a scrap yard, and I had him change the thermostat. I bought all the stuff to do that and a radiator flush, and I couldn't find the darn petcock! So after an embarrassing half hour digging, I decided just to bring him the car. He looked and said there was no petcock (awesome!) but did the flush and replaced the thermostat anyway. Also, plug 1 was fouled (p301 anyone?), so that was replaced. Other plugs look fine.

50 miles later? p301 is back.

Ok, Blazer. It's on.

Next up? I think I'll check the coil(s), the O2 sensor, the valve cover gasket, and the cat. If those check out, wires. If that doesn't fix it, cap and rotor. The fuel rail is brand new, so it's unlikely to be an injector problem (fingers crossed).

Any other thoughts? Or even a "I'd be doing what you're doing." ?

 

What did the plug look like? Could it be oil fouling (leaking valve seals) or maybe a lack of compression which is not allowing cylinder temperatures to reach high enough values to burn clean?

 

Update:

Took 3 trips to the inspection station, another distributor cap, fuel system cleaner, two plug wires, 2 plugs, a little magic and a lot of patience, but the car passed inspection.

Within 50 miles, bam SES. p0410 and p0301.

p0410 was addressed by changing the 30A fuse next to the battery, which had blown. I've still got some stuttering on acceleration and a p0301.

The SES light flashed for like 5 seconds the other daym which sent me into a panic, but then it stopped and was steady again.

Re: your last question (which I missed, sorry). The plug did look like it had oil on it, so I should be checking the valve seals and if they're cool, the coils?

I'm not sure how to check either of those, but I'll sniff around on the forum and do some google searches and hopefully come up with something.

Thanks again for all your help.

 

UPDATE:

Behavior of the Blazer seems to have stabilized. Predictably, the following occurs:

When the gas tank gets to about 1/4-1/2 tank, the SES light comes on and throws code p0301.

Upon refilling the tank, it takes approx 50 miles for the light to go off. Then the light is off for appx 100 miles before we're somewhere between 1/4 and 1/2 tank again (local driving), and the light comes back on.

Performance (shaking, etc.) is noticeably worse under 3/8 tank, and it really feels like it's going to stall by the time the fuel light comes on.

I had fuel issues and changed the fuel filter about 8 months (< 6k miles) ago, and the new one got all gunked up and actually rotted through in < 1 month. Put a new one in and that one seems to be doing its job.

Thoughts?

 

Update:

Friend used some kind of magic scantool to diagnose the RPM/speed at which the misfires were occurring and found 2 bad grounds because of this. These were fixed. We did a fuel pressure test, and it was barely acceptable, so the fuel pump was replaced. The car still rattles/vibrates at low fuel, so the new theory is that there might be an evap problem. BUT, the SES light has not come on since these repairs were made, so something good is happening apparently.

Had a high-pitched scraping or grinding noise from the front driver's side wheel when I was driving recently, and it went away when I hit the brake. It started up again, typically, when I'd turn, and then it would stay around until I hit the brake. This was a stuck caliper, and it actually cracked the pad on one side (I guess due to heat), so I had to do a whole brake job on it.

If it's not one thing, it's another. Just recharged my AC for the season, and we're blowing cold, so maybe I can settle down on the repairs for awhile.

In any case, the car's paid off, and I've been driving it 10 years, and I hope to be driving it another 10. The repairs are cheaper than payments on a new (equivalent) car, and I'm learning a helluva lot in the process.

Cheers.