help!
 

I had this problem about a year ago, and now it's happening again. If I drive my blazer for more than 15-20 miles or so, it will die. As I'm driving, it's like the fuel just gets cut off. If I take my foot off the accelerator, it will stay running until I come to a stop. But, if I try to give it some gas, it cuts out. Either way, it dies eventually. It will start right up, sometimes a little hesitant, and sometimes has a rich smell, but it starts. I can drive it for another quarter mile or so before it happens again. If I let it cool down for a day or two, it's fine until I take another lengthy trip. I've replaced the MAF sensor, MAP sensor, fuel pump, plugs, wires, and some other sensors I can't remember right now, but nothing has helped. I ran the code reader, and it pulls up P1870, P0101, and P0442. I've looked all of them up, and it doesn't seem like anything is related to the problem I'm having. I'm tired of Googling and coming up with nothing. Please help. I'm debating throwing it on Craigslist and just buying something else. If you have questions, don't hesitate to ask.. I tried to describe it the best I could.

It sounds to me like its your ignition switch. That exact problem has happened to a few other people on here (including me) and the culprit was the ignition switch.

But im not 100% sure on that. When you did the fuel pump what brand did you use? if you used Airtex that could also be your problem. NEVER use anything other than Ac Delco or Delphi on these trucks. Same goes with wires, plugs, cap, and rotors.

But it really sounds like its your ignition switch if it all of a sudden dies, because what happens is after driving for a while the ignition switch heats up due to bad insulation over the years and will basically cut off power to the fuel pump. Thats my understanding anyway. The bad switch could also be setting off those codes.

If a lot of random things start happening to your truck that cant be explained then its most likely the ignition switch.

Codes:
P0101 - Mass Air Flow System Performance
P0442 - Evaporative Emission Control System Leak Detected (small leak)
P1870 - Transmission Component Slipping

As 97cb stated, it is possible that the ignition switch is causing the stall, but I doubt it is responsible for all of these codes. You can test the ignition switch with a multimeter using the information found in my signature below.

My first thought was a plugged catalytic converter. As they get worse, they can cause an underload studder and eventual stall as the restriction gets too great. The restriction can be dependent on heat buildup in the converter. Do you hear any rattling? How about if you smack the underside of the converter with a 2x4?

That crossed my mind as well, but it doesn't studder at all. It just dies. Like I turn the key off or something. It's instant. I know the other codes are unrelated, but I was just stating what all is there.. I don't have any rattle from the cat, and there's no problem with power on acceleration, or even cruising at highway speeds.. how much am I looking to spend on an ignition switch?

Test things first unless you like wasting your time & money.

The MAF sensor performance code could cause the engine to die as well so you may want to diagnose that first.

well, I replaced the MAF sensor a few months ago, and never reset the check engine light. That's what I originally thought the problem was.. It did help it run smoother, but didn't fix the random stalling. I reset the light last night, so when it comes back on, if it does, I will see what it is.. I'm guessing the emission leak code is because I have a small crack in the exhaust manifold, and the tranny code is something else I've read up on, and is what's causing it to shift hard from 1-2 gears. So with all of that, none of the codes are really related to the problem. Would the ignition switch throw the light?