Ok, here we go!

This post relates to a 2.5L 6 cyl 2000 Mazda 626 with a 5 speed manual transmission.

I replaced the alternator, it needed to be done

The next day when I would drive freeway the car would drop power between 3000-4000RPM (between 60-80 MPH)

Then one day - poof!
Rough idle - no accelaration - WHITE smoke from exhaust

Checked codes -
Random Misfire
All 6 cylinder misfire
Lean condition
Camshaft position sensor
EGR Valve
Mass Airflow sensor

Changed plugs
Removed air intake system down to the EGR valve but couldn't get the exhaust pipe off - banged on it a bit to try to break some carbon free - probably worthless.
Cleaned the ports behind the throttle body in the intake manifold the best that I could. Cleaned the throttle body to a shining gleam

Put it all back together - ANNNNND. No luck. Still a rough idle and no accelaration .

Lots of white smoke from engine and exhaust .

Any suggestions?

There is no coolant in the oil resovire
I understand it could be the head gasket, but if it's not, where is the issue.

I have no replaced the camshaft position sensor or mass airflow sensor

But, the mass airflow sensor looked good

I'm not about to replace anything that I don't need to replace .I was thinking it could have been or could be the camshaft position sensor but that doesn't explain the white smoke .

My valve cover is leaking so I'm sure oil is dripping on to the plugs.

The main thing I need to figure out is why there's no acceleration.

Any advice or suggestions would be greatly appreciated
Thank you!

The white smoke coming from the engine could have been coming from the throttle body/carcb leaner I sprayed into the intake manifold ports right behind the throttle body

 

I have the same model and have a P0400 code and the same stalling issue. Did you ever figure this out? I'm thinking of trying to replace the EGR but I hear it's a b*tch.