I’m at a loss with this 03 blazer ls sitting in my garage.
Ive owned it 8yrs and the last 5 it’s been on jack stands.
My background is mechanic/welder/custom fab, but I’ve never liked electrical. Haha. Also at 6’8” with a bad back this isn’t fun anymore at 45yrs old. Haha. Its only seen top quality parts as I never planned to sell it. So here is the last 500mi after the domino effect started. These are all new parts!

built 4l60e, new silicone vacuum lines.
1st spider assembly replaced due to #5 not working.
2nd gm spider assembly w/pressure reg. gm fuel parts; pump, purge valve, evap valve, filler hose, filter, upper fuel lines, etc, to remove any chance of internal rust or contamination.

took awhile to start, acted as if was flooded. got that all cleaned out. but still running like crap.
Now it’s saying PO200 #3 inj not getting pulse?!?! Wtf??

My only guess left is the ecm? Idk...
I’m tired of throwing money at it....
I just want it to run. Please help!

Thank you ahead of time for any replies!
So much appreciated!

 

First thing I would do is pull out the injector connector on the top of the intake manifold and make sure you didn't accidentally damage any pins when you plugged it back in.

 

Turns out I bent a prong. Was able to straighten it and all injectors are working,
thanks for the help!
the thing still pings, but it’s done that since I bought it. (Dieseling sound under any load) and am guessing it’s the ecm. I’ve replaced everything else for it...(knock sensor, maf, coil, module, etc....

 

Glad it worked out. Does your engine have EGR? You might pull off the valve and make sure the passage isn't plugged (start it up for a second with the valve removed). Lack of EGR flow could cause the pinging you're getting.

 

No egr or it would be new by now.
It’s pinged since I’ve owned it the last 9yrs and I’m about to give up and sell/swap it for an older jeep. Tired of fabricating or searching for everything.
All “relevant” new parts: fuel system from injectors back to filler hose assembly, entire Ignition system been replaced a couple times. Knock sensor, O2 sensors, performance cat with 2.5” single exhaust manifolds back, maf, iac valve, cam sensor, upper and lower intakes with blend of fel pro or ac delco gaskets. Throttle body cleaned every 30k
premium gas, seafoamed vacuum line, crankcase previous fuel system a few times.
Zero, Nadda, nothing... random misfire codes stopped, but it pings/diesels hitting the throttle at any moment in gear.
my guess is ecm. I’m really at a loss
I’d light it on fire but then I wouldn’t have anything for winter! Lol

 

You would have a nice warm fire!!