I have a no start issue, after I replaced my fuel pump fuel relay, all injectors and afm-maf unit. It stutters and stumbles yet will not stay lit. I don’t have voltage at my injectors like the CPS is faulty. I do Have spark and timing is right on. My question is… do I replace the dizzy or is it a ecu issue?

 

From your description the truck will start but does not stay running and stumbles? You may have a vacuum leak somewhere. If it is starting it has to be getting fuel either from the cold start injector or the rail injectors. I would start with the verifying the hoses and the intake plenum is sealed. Then move onto verification of the injector firing. In my experience this injector pulse signal is too quick to catch on a DMM and you will need to find or buy a scope device to catch the injector pulse. The ECM's are rather stout. Ive kicked myself for replacing one and it wasn't the issue at all.

 

Please start with what year and what engine/trans.
Did it run before you replaced these items or are these the things you replace to try fixing the no start?
if it doesn't run how did you determine the timing "is right on"?
if it stutters and stumbles it is getting spark so your dizzy isn't likely to be the issue and it is at least getting "some" fuel.
Does "fuel pump fuel relay" mean you replaced the pump and relay or just the relay?
How long has it been sitting? Water in the fuel? Fuel filter? Fuel pressure?