Wiring diagrams on a 4.3 vortec

Did you change the spark plug wires and coils? That is usually the main cause of a miss in a cylinder.

Well i bought a book we have a 2009. Doesnt show the wiring diagram to the knock sensor, ones on used engine are cut and dont know which ones to wire them up too . any other suggestions

http://www.youtube.com/watch?v=_igbV3-67v4

the cap should be marked on a vortec 4.3 liter. the left side of engine is from front #1 #3 and #5 cylinders. the right side from front is #2 #4 and #6.

It is located in the valley between the cylinder heads under the intake manifold.

the knock sensor is back beside the base of the distributor.

The color codes will be different so when you take the harness off the 95 make sure that you label ALL the connectors to make it easier to install it on your Blazer. You may also have to change some sensors or switches up to 95 so that the harness will fit. Label all the empty connectors with their location in the 95 because they will be for options that may or may not be on your Blazer. If you have to access a wire diagram to complete the job then use the 95. DON'T let someone else take the 95 harness out for you andtake a rough diagram of your truck with the plug-ins marked for location and # of pins for wires. Basically it should fit but attention to detail is a must.
Also check out faxonautoliterature. They list GM service manuals but also GM books for engine interchanges that may prove to be very helpful. Hope this helps.

hi i havw a 3500g 1998 vortec we have no constant spark we need to find a wiring diagram whats the best sie to use not sure if some thing is wrong with the plug to the coil?

Here is a wiring diagram from distributor cap to spark plugs. the firing order is 1-8-4-3-6-5-7-2. I hope this helps you.

check the throttle pos sens