So as far as the blazer leaving me on the side of the road only 3km from home, here is the more in-depth version. I was going up the hill to my neighborhood about 60km/h constant speed, rpm, throttle, and all of a sudden it cuts out and I had no power at all, the gas pedal had no change on the engine and I was seemingly just coasting, however, the engine was still running and just idling, it cut back in when I jabbed the gas pedal down a bit more and felt normal for a few seconds until it cut out again, the same thing repeated itself and I knew I had to get off the road so I turned at the closest intersection and onto a side hill. I was going up the side hill looking for a nice place to stop and have a look at things when it died going up the hill and I coasted it to the side of the road, it started up again but I could tell it was running rough, it would idle ok but showed misfires on all cylinders and stumble when I gave it gas. It had no power to move anymore up the hill and I was stuck in place, it was showing 2 new pending codes I did not expect to see, P0172 and P0175 for rich on both banks. After waiting 15 minutes or so I started it up again and it ran seemingly better, good enough to limp home without more problems. Once I was home and unpacked the blazer and gave it a nice clean it was time to look into some things, first thing was fuel pressure and it showed 58 psi and didn't leak down, I checked it while running and was seeing some large fluctuations at idle but other than that would idle 50-52psi when not fluctuating. I then looked into the rich codes a bit, the scanner was indeed showing the engine was running a bit rich on both banks, rich enough to set the code. So I first saw the fuel trims more normal in open loop and go rich once in closed loop, I also saw the fuel trims change from -12.5% LTFT on both banks to lean with just unplugging the MAF. It's also worth noting when I plugged the MAF back in and it was back in closed loop the fuel trims stayed normal.

Now that I have had a look at things and taken it for a few drives without the issue happening again, I'm thinking the fuel pump must be to blame. The reason being is it must be an intermittent issue that can make the engine cut out and stall seemingly out of the blue, either fuel, spark, or air delivery must be effected. Given the fact when the problem was happening the truck would idle but have no power to go up the hill I was on and would stumble even when giving it gas in park, I am convinced the problem lies in either the air or fuel delivery. Now I'm about ready to put a new Delphi pump in as I need to have my truck back in working order to start work here. What do you guys think? What would you guys do if you had checked over what I have and hadn't found anything, and can't seem make the problem present itself again by driving it around more.

 

I used to have a TBI s10 that would do very similar to what you describe, one time every month or two - just die going down the road and refuse to start until I had sat for 15 minutes or somehow moved the wiring harness just right. After a year or so of this I finally replaced the entire engine wiring harness with another from junkyard and it never did it again. It could have been the wiring was bad, or it could have been a bad connection - but it was electrical. Bottom line - at this point you just don't know unless you catch it in the act with the right tools. It could be fuel pump but it still may die going to work the first day after putting it on. I would wait to see if it becomes a problem where it can be diagnosed better.

That said - Great Trip!! I'm sure you will remember it for many years to come!!

 

Thanks Les! It was a spectacular trip, a real dream come true to travel across my country and see everything. Even more, I was able to do it in this blazer which makes it all the more special to me. Seeing it perform day after day rain or shine and putting down about 1000km most days without even breaking a sweat was remarkable, a lot of work to get it to this point. I got the blazer at 242kms, engine blew at 250, and I left for the trip at 272, I'm now sitting at 291. So I've put about 50k on it in almost 5 years of ownership and 19k was in the last month, I find that insane!

Thanks for keeping my mind open with the problem I'm having, I may go take it into town today and run some errands maybe I can get it to act up again. It will definitely be a hard one to diagnose, not a hiccup for 19000kms then out of the blue it just dies! I will also add it was about 44 degrees outside when it happened so the hottest temperatures across the country, that may have played a role in it as well. I forgot to add that while I was diagnosing it the P0172 and 175 codes went away on their own. I will say when it happened it was a distinct cut out, one second all was fine, and the next it just cut out and was idling, then the same thing when it cut back in. I'm not sure how else to describe it. After it had died and I had it idling again but it wouldn't go anywhere it felt like something was choking the engine and very weak. I'll see if I can make it happen again today, but I'm not sure what else could fail like that, it felt like a fuel delivery problem. The fuel pump is also about the only thing that I haven't replaced and tinkered with in the fuel and air delivery systems, I'm thinking it may be worth while to finally make the fuel pump pressure tester and test the max output, especially with the fluctuations I was seeing at idle, just no parts stores near me ever have that Dorman part you need to connect to the fuel filter connector!

 

Amazon sells Dorman stuff IIRC
so what's your first job out of school?