So my mom's GMC started acting up a couple months ago, it started off by consuming a considerable more fuel, then it started having a hard time cranking up. And eventually it started bogging at stops and sputtering under hard acceleration. At first I thought it was the fuel pump so I dropped the tank and replaced it, the problem went away for about 3 weeks and then it came back, I thought it was a faulty unit so I had it replaced under warranty and I dropped the tank again to replace it. This time the problem came back after 3 days and much worse. Now it was smoking black and very rough idle, would bog under acceleration etc.
So through a very painful drive down to Autozone I got diagnostics ran on it, it had a laundry list of codes, can't remember them all off the top of my head but some of them were misfire in random cylinders, air/fuel mix, o2 sensor, and a couple others I can't remember.
I rented a fuel pressure tester and it holds pressure when I shut it off but while it was running it had a pressure over 100 psi, I couldn't read exactly where because it just maxed out the gauge. I called a tech at the dealership and he told me it should only have an idle fuel pressure around 54-59 or something like that so I figured the smoking issue could be that it's just running pig rich. So I opened up the manifold to look at the spider injectors and the rear regulator was leaking when I primed it so I decided to replace the whole unit, after that I put it back together again and the problem is the exact same, no change in behaviors.
Ran diagnostics again and there's fewer codes, but I am still getting a MAP sensor, air/fuel mix, and random misfire. So I went to the junk yard and got a throttle body off a 2000 blazer and put it on the jimmy to test if it was a bad sensor but still no change.
At this point I'm about to give up and drag it down to Tunex and let them figure it out unless someone can help me with additional ideas on what the problem could be? I hope this made sense. I'm on my phone typing this up.
So through a very painful drive down to Autozone I got diagnostics ran on it, it had a laundry list of codes, can't remember them all off the top of my head but some of them were misfire in random cylinders, air/fuel mix, o2 sensor, and a couple others I can't remember.
I rented a fuel pressure tester and it holds pressure when I shut it off but while it was running it had a pressure over 100 psi, I couldn't read exactly where because it just maxed out the gauge. I called a tech at the dealership and he told me it should only have an idle fuel pressure around 54-59 or something like that so I figured the smoking issue could be that it's just running pig rich. So I opened up the manifold to look at the spider injectors and the rear regulator was leaking when I primed it so I decided to replace the whole unit, after that I put it back together again and the problem is the exact same, no change in behaviors.
Ran diagnostics again and there's fewer codes, but I am still getting a MAP sensor, air/fuel mix, and random misfire. So I went to the junk yard and got a throttle body off a 2000 blazer and put it on the jimmy to test if it was a bad sensor but still no change.
At this point I'm about to give up and drag it down to Tunex and let them figure it out unless someone can help me with additional ideas on what the problem could be? I hope this made sense. I'm on my phone typing this up.
