Cranks and stumbles, but No Start
 

2000 Blazer LS 4.6 Vortec

Alright guys Im at my wits end with this thing. Ill list out what I have checked and tested and see if anyone can come up with something new for me to check.

Story leading up to the No Start
While driving I noticed a lack of power and no top end. Once I would get to about 65mph it would downshift and just didnt really have much past that. The CEL came on and gave me a P102(MAF low input) code. I pulled over and unplugged the MAF and continued on my way. Top speed increased to ~80mph, and fuel economy was back to semi normal. I picked up a clean looking MAF from the junk yard and installed it. The car started perfectly as it was normally doing and I revved it slowly up to 4000rpm 2 times. Then I went for a test drive and as soon as I put it into drive and tried to accelerate it was stumbling and would not accelerate past 1500 rpm. I parked the car and went back to it the next afternoon and it would hit on 1-2 cylinders, but never start.

To date my diagnostics include
-Installing a known good coil
-Installing a known good ECU
-installing a Junk yard ICM(no change at all)
-Installing a new CPS
-Installing new Plug wires(old ones had open's in 3 of the 6)
-Swapping out a known good distributor cap
-Fuel pressure check Key On Engine Off 55psi
-Fuel pressure while cranking increases to 60psi
-Crank to distributor timing is spot on using the 6 under the cap and second line on the balancer.
-Compression on cylinders 5, 4, 6 all read 170psi, I didnt check the others yet, but figure it should start and stumble on 3 and it was running smooth prior to failure.
-Checked ground from back firewall to battery ground .02 V drop.
-Replaced spider injector with AC Delco MFI conversion
-Cat was replaced last summer

Anyone have any ideas, this thing is destine for the Junk yard if I cant get this in the next few weeks.
Now the only thing I can see is while cranking the timing advance sits at 0*. I have looked for a timing reset wire in the passanger compartment, but I have since learned that is not there on the 2000 model.

How's the spark plug condition?...could throw in some $2 delco copper's and see if it starts.
Make sure plug wires are in the correct order.
Maybe bad dizzy or rotor, or another bad maf...or iat?
Maybe crank signal, but you'd think that would throw a code along with the maf or iat

For fuel leakdown your pressure must be: KOEO 60-66 psi while fuel pump is running, then not drop down below 55psi for at least 10 minutes. Don't start the truck at all through this procedure. If you are getting a good bright blue spark at the end of your wires/spark plugs, it seems more like a fuel pressure issue from what you describe.

So I'm right at the lines for fuel pressure. 60 KOEO and 55 for 10. All that was replaced with the injector kit. Spark jumps a 1" gap at the coil inline to the cap. I'm going to finish compreesion on all cylinders and try plugs next. Then rotor since that is all I have not done. How can the rotor fail? It seems to be a piece of steel to conduct through and there is not a buildup on the tip of it. I'll update on Tuesday or Wednesday when I have a chance again.

So compression is steady across all cylinders at 160-175.
New plugs and cap and rotor and still stumbles once or twice but no start.

I dunno bud, try a shot of starting fluid and see if it runs.

I tried that too and nothing. It is not worth more investment. I'm going to cut my losses and junk the car and remove all the parts I just installed . Looking at 2 blazers for sale in the area that need tires and a tune up. These parts will work nicely and it runs.