I have a 96 blazer 4.3 4x4 that let me on the roadside a while back. I changed the fuel pressure regulator because of hard starting for quit a while and rough idle, plus a mechanic hooked it up and check it out and told me it was the fpr. It ran great for four days before stranding me, it had no acceleration when I gave it gas, backfired twice and then shut off, and won't restart. When I changed the fpr the new one had two o-rings and the one I took off only had the larger one on the back of the regulator. There wasn't any material in the box so I figured that's how it was supposed to be and put the smaller o-ring on the new one also, it's the end that fits into the plunger in the spider assembly. It was hard to get the new fpr to fit and to get the retaining clip to fit over the fpr and lock it into place. Anyone know if one way or the other is right, I'm just concerned maybe something I did has something to do with the truck quitting while driving. Maybe the new fpr popped out or something, it took 4 hours to do the job and I would hate to have to take it apart again unless I have to. Thanks for any help.

 

the easiest way to check it is to pull the upper plenum back off and turn the key to the "on" position to cycle the fuel pump and check for leaks.