Okay, I've got a 2001 Jimmy, that will be driving fine one minute and the next it stalls out while driving, or it will be driving fine all day then the next morning won't start.

ICM -- replaced 7 months ago
Fuel pump -- replaced two months ago
Fuel filter -- replaced two months ago
IAC -- replaced last week
Alternator -- checked, good
Battery -- checked, good

Any ideas would be greatly appreciated.

 

Any codes?

It's just running fine, then shuts off, or it runs real rough, and eventually stalls?

I know you said you changed the fuel pump. Was there a fuel pressure issue? Possibly a problem with the injector/regulator

 

...as for the pump. we recently had a topic "why is my truck eating fuel pumps", where OP has been replacing fuel pumps over again every two months or so. I wouldn't trust records, but do the tests. Scanner may give You some of idea what happens, if You look up the fuel trims.

 

It runs just fine, no rough running, no chugging, just shuts off.
Fuel pressure is good, 58 PSI, leak down test is good too.

My truck doesn't seem to eat fuel pumps, it does like the taste of ICMs though, so I wouldn't put that out of the running for cause either.

 

I know that thread all too well... Lol


Knock on wood, but I think I might have gotten on the good side of the fuel pump gods. New ac Delco pump, replaced the filter and the lines from the filter back, rebuilt the electrical connector (I've got a buddy with the tools to do weatherpacks) and washed out the tank. Seems to be holding

 

@cleburne red
LOL I didn't remember it was You. I'm glad You didn't scrap Your ride, cause You wouldn't be here on BF

As for the topic, if it runs fine and never rough, that would rule out the spider. Fuel test rules out the fuel pump. Except, the problem is intermittent, so best would be to check the fuel pump i.e. when the ride was settled over a night and doesn't want to start.

As for the ignition - the very basic test is to check for 1" strong spark.

Intermittent problems are generally PITA, so the main problem is to perform the tests, when it exists.

 

My buddy has been trying to get me to pick up a first gen 4runner, like he recently bought. I'm too invested in the Blazer, though, and I've kinda grown attached to it over the last eight years or so that I've had it

 

This is getting aggravating.

The random stalls and no starts continues.
Trying to track it down I checked the fuel pressure and done a leak down test, so not the fuel; has to be ignition or electronic ...something.
I've now replaced:
IAC
ICM
Ignition switch and lock cylinder

It's not throwing any codes, ran great for a few days and now this morning.....no start.

If I had any hair left I'd being pulling it out.
SOMEONE PLEASE HELP!!!!!

 

When it's not starting, you getting any spark?

 

So no spark.
Don't know if this might be as simple as this, when it did no start this morning I was just checking connections and trying to start it up, after I "pushed in" the connectors for the coil and ICM it started right up. did some research and found the pigtails (standard motor S551 & S656) ordered them from amazon and will be here tomorrow, so I'll splice them in and see if it really could be that simple.