Good afternoon all, I just inherited my late uncles 2001 Chevy Blazer 2wd. It has a CEL on for Cylinder 4 misfire and code for idle higher than normal.

my main concern right now is the Cylinder 4 misfire.

I have Changed the plugs, changed the whole injector spider, did a compression test on 1,5,2,4,6. Couldnt get to 3 at the time but wasnt worried about it as all the numbers were within 2psi on the others.

any tips or suggestions on where to check next? This is going to be my oldest daughters first car so I want it to be safe and reliable for her to get back and forth to school and when she finds her first job.

 

My guess would be a vacuum leak in the vicinity of cylinder #4. Bad intake gasket, maybe? Leaking seal on MAP sensor?

 

I appreciate the response. I do need to replace all the vacuum lines. multiple are split/broke. I replaced the spider injection system today and put new gaskets. I sprayed brake cleaner all around the intake area and didnt get any surges from it. My last thing to replace when it arrives Tuesday is all the plug wires and a whole new distributor. I took the cap off and see some burn marks where it seems the spark may be jumping, so I figured Id replace the while thing. The blazer has 194k miles on it.

Happen to know where I can get a good complete Vacuum Diagram so I can be sure to not miss any of them?

 

I do not have a complete vacuum diagram...would be nice to have....but the lines in the engine bay are usually the ones that rot. The lines for the HVAC usually stay good as they are not exposed to engine heat.
Hopefully you have all the lines there although may be split....least you would be able to determine where the ends go. Also with a 2wd you have fewer lines.

Take pictures and post here if you have questions...we should be able to help you out.

 

This isn't a very good diagram, but it should help. I assume the one under your hood is no longer there?