1999 Blazer vortec w vin 4x4 that has 267k on it. My issue at the moment is it has a very rough idle after it has sat at a red light or in traffic. When i am accelerating or driving the rough idle is gone lastly accompaning there is a misfire it's on cylinder 3 sporadic at best. I've had that checked but at the moment there are no codes. Recently I replace the MAP sensor, the spark plugs, spark plug wires, the distrubter cap and rotor button, fuel pump 3 months ago the tps the could by the icm, the egr valve some vacuum limes but still the rough idle persists. Any suggestions or procedures

 

Check you injector plug on top the intake plenum. It is the black square plug. After you have checked it. If noting is amiss then run a compression test on your suspected cylinder with the misfire.
Remember don't throw parts at a problem. Take your time and test stuff.

 

Sorry about that I neglected to mention I also had a compression test done at Pep Boys when I had them run a full diagnostic all they could tell me was my compression was good and I had a cracked spark plug replaced all the spark plugs and it changed nothing. The black plug you mentioned it has a sideways connector coming into it from the passenger side and has a lot of metal prongs sticking into it sorry is the best description I got off the top of my head when I check it what I look for corrosion or anything like that

 

Yes. The black square plug with all the metal prongs. This is your fuel injector power supply. You are looking for corrosion or the big black square plug it self is not making good contact. As in it is not pushed all the way down onto the fuel injector pins.

 

Well truth be told when I removed it I didn't see any corrosion on the inside the plug itself I did not check the actual wires coming from the plug does labor wrapped I will check that the Pens seem to be just fine let's try to clean this damn thing on my engine when I put it back down I pressed on it very firmly on both sides make sure it was clicked all the way in and all the way down

 

I left out one very important factor if you're near the exhaust it smells very very rich like there's a lot of extra gas being not burnt do you think it could be a fuel pressure regulator that is just bad

 

If it is your fuel pressure regulator then you will normally have a miss on cylinder 6 and 5. As they are the two closes cylinders to the fuel presser regulator. The fuel pressure regulator is located under the upper intake. It is attached to the rear of the fuel spider. Very easy job if you have some mechanical ability.

 

Sweet. I do just not much with this engine top end removal just yet

 

Here is an exploded view of the fuel presser regulator under the intake. If you do plan on replacing the fuel presser regulator your self make sure to remove both o rings.

 

Excellent advice right there I'm actually thinking about changing the regular spider over to a multi port fuel injection spider I read a lot about it a lot of people seem to think it's a good idea and their vehicle runs better. Any suggestions or input on that one