97 Blazer runs rough

I posted a message a few days ago about my hard to start and rough running Blazer. Since then I was able to get the ODBII codes. P0300 misfire. P1406 Auxiliary emissions control, and P0442 small emission control leak.
The guy from Auto Zone said it could be a of of things and I should take it to a shop for a better analysis. I have replaced everything electrical. The fuel pressure checks ok but drops after the pump cuts out during the start. Any thoughts as to what I should check next.
Jim
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first thing to check with the fuel pressure dropping is more than likely your fuel pressure regulator is leaking and if im not mistaken , om that motor it is all one piece with the injectors....happy hunting hope i helped
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(Reply inline) 97 Blazer runs rough (I hate it when this happens)
Group: alt.autos.4x4.chevy-trucks Date: Thu, Oct 16, 2003, 2:28pm (CDT+1) From: snipped-for-privacy@home.com (jk) I posted a message a few days ago about my hard to start and rough running Blazer. (Sure you did)
Since then I was able to get the ODBII codes. P0300 misfire. P1406 Auxiliary emissions control, and P0442 small emission control leak
(What was the history records on these codes ? and what cylinder did they say was misfiring?)
The guy from Auto Zone (OH this explains it . HEY was the guys mane DJ HATT and did he carry a manual with him?)
said it could be a of of things and I should take it to a shop for a better analysis.
(You should have done this in the first place. AUTO ZONE PARTS STORE not Auto Zone full service garage....)
I have replaced everything electrical (Why you do that if you didnt know what the problem was ..Oh the guy at Auto Zone must have told you to.
The fuel pressure checks ok but drops after the pump cuts out during the start.
(The cuts out or the truck stalls?When its running does the fuel pressure jump? How much pressure do you have?
Any thoughts as to what I should check next.
(After thinking really hard and drinking a Beer. I think you should hmmmm. Well he did goto Auto Zone for a diagnosis.....HMMMM you could ask Hatt what his manual says or you can do this. You have a misfire code since you dont know which cylinder it is first check your plugs, wires,Cap and button....'If all is good check your injectors for carbon buildup (a clogged injector will cause a misfire) Does your truck idle check your fuel pressure. Does the pressure jump or drop at idle ? If you pressure is jumping stop and get a fuel pump. A bad fuel pump will also give you a misfire at multiple cylinders. Since you have a emissions code you may have a leak somewhere in you evap system. Which if its small can only be found using a smoke machine to shoot smoke through your system (it shows you where the leak is) Which both codes go togeather if you get a PO422 it will set of code P1406 (which is just a fault code) and PO422 is your fault . It would be much wiser to go some where to give you a full diagnostic reading then to goto Auto Zone for a code pull... There is much more to it than just getting codes ...
Steve C (Got another beer and waiting for another great saga from the Marsh Monster)
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