Im looking for help on my 98 blazer has the 4.3v6 4x4 it has a P0300 random misfire code and a P0405 code I have thrown so many parts at this thing and I still can't figure it out. I have just put a new EGR valve, replaced all 6 plugs, new distributor cap and rotor, and a bunch of other parts didn't make a difference. Please help!

 

Is the truck running fine though? Sometimes the CEL (check engine light) will just be on because these are some old vehicles.

 

No it isn't at all it runs very bad it idles rough and when put in drives it stalls sometimes and if I try to drive it it takes roughly 15 seconds to reach 30 mph

 

Have you checked the ignition coil and ignition control module?

 

Yes actually. I am beginning to think the spider injection system is failing but I really don't want that to be the case.

 

That could be it. You check the fuel pump and fuel filter while you at it? I'm reading the repair manual and trying to derive what else it could be.

From the manual

 

probably not helpfull,but i have a 98 jimmy with 200k,just did the intake gaskets,put the old spider back in...runs fine..if you ever upgrade the spider,youall see what a PAIN in the *** they are....did you try looking at it running in the dark,looking for any arcing?

 

You need to start with the fuel pressure leak down test. Then check your EGR wiring, voltage and ground.

George

 

Update?

 

I ended up selling the blazer as everything checked out and it got too much lol. Thanks for all the help everyone!