Originally Posted by Deane138

Hey,

So I purchased a Mazda Protege 2002 Hatchback manual that had a blown head gasket, I replaced that and surfaced the head, no issues there.

However, now when it starts it starts up fine, idles at 1200ish then eases down to about 500-600 rpm but as it sits there after a while it starts misfiring and eventually dies, if i take it for a drive i have NO power if im in a higher gear and under load, it jumps and coughs like it's completely missing something in the combustion side of things.

SO FAR:
I've replaced:
Fuel pump,
Fuel filter
Fuel Pressure Regulator (the pressure is good at 30-36 psi as per spec and doesnt jump around even during loss of power)
Head Gasket
Ignition packs
spark plugs
Valve cover gasket
intake tube between Mass Airflow Sensor and intake manifold


I've checked:
Mass airflow sensor (readings are within the specs 0.8 - 2.2v at idle)
Throttle Position sensor (reading within the specs of CTP 0.1 - 1.1v and WOT 3.0-4.6v)
Looked for vacuum leaks found nothing


The EGR has been removed previously, From what i can tell it's blocked off but will pull the intake to confirm.

Any ideas or help would be MUCH appreciated as im currenly defeated, i dont know why it wont stay running.Cheers,