My blazer is continuing to misfire. I have replace the plugs, wires, throttle sensor, and cleaned the MAF. After changing the plugs the code erased, but I am still having the misfire. It occurs when revved at idle, at approx 15mph, and approx 25mph. Gets real sluggish and has no power. Before the misfire conditions I had recently replace the air filter with a K&N air filter. I read somewhere that this could be a possible reason due to the oil that is used on the filter causing oil to dirty the thermistors on the MAF sensor? Any guidance is appreciated.

 

Have you checked the fuel pressure? If so what is it? If not i would check it! These motors require 60-66 key on engine off . I heard somewhere on here that that poppets on the spider injection dont open properly with less then 52psi !! Also were the plugs wet or fouled when you replaced them? If they were wet that could mean a spark issue or engine issue ,if they were dry that would most likely mean a fuel related issue..I say most likely !!!! not always!!!

 

Is the SES light on now? Does the SES light blink when you feel the misfire? The bit about the K&N filters contaminating the MAF sensor is true! Did you install AC Delco spark plugs? Did you replace the distributor cap & rotor with AC Delco parts? (very important if you want it to run well). As for the poppets, they start messing up when fuel pressure drops below 60psi and will not squirt at all if pressure drops below ~43psi.

 

https://blazerforum.com/forum/2nd-ge...version-62423/