Remove them and take them to AutoZone, Advance Auto, etc. and they will test them for you for free. Make sure they cycle them enough to get them hot.

 

UPDATE:

I took the ignition coil to auto zone and they said that they cannot test it for my particular vehicle. Any other ideas? I went to talk to my old shop teacher and he said that my distributor might be bad. We looked at the cap and saw that cylinders 3 and 6 are opposite corners of each other on the cap and if the distributor is wobbling, it could cause the misfire. He also said that the ports for where the fuel injectors enter on the plenum might be dirty. I never looked down there to see the condition when I did the MFI conversion. If my coil were bad, wouldn't I have a random misfire, instead of a multiple misfire like I'm having, unless the firing order could possibly affect it in some way. Same thing for my lower intake gasket since it has not been replaced yet? Unless maybe it was just bad in those areas around the cylinders? Oh and I have an update as to the misfire. I can rev it up while the car is stationary in park or neutral and the check engine light will go off now. It did it before I changed everything and then it went away after I replaced all these parts, and now this happens again. The last time I revved it up today, the check engine light didn't flash and then go away, it just stayed lit. Also, when I hooked up the scanner, it showed that 3 and 6 still misfire the most. What did change was that at idle, it will hardly misfire and sometimes won't even show up on the scanner on some cycles, but as I give it gas, 3 acts up more than 6, and when I get to an RPM where the check engine light throws a code, 3 and 6 misfire at nearly identical rates and 3 used to always misfire more, especially at those RPM's. Cylinder 1 still misfires but on a very very rare occasion, whether it's idling or I am revving it up. I noticed that cylinder 4 also showed a misfire on the scanner. Cylinder 1 has a history of 12 misfires, cylinder 3 has a history of nearly 19,000 misfires, cylinder 4 has a history of 4 misfires, and cylinder 6 has a history of nearly 13,000 misfires. Don't know if that maybe will help pinpoint the problem or not. I am trying not to move it until I get it fixed. I drive my other car and only move my Blazer to take it to my shop and back home and test drive it after I change or do something. I don't wanna make my problem even worse. Hopefully this can help bring up some more ideas. Thanks guys, I appreciate it.

 

Anyone have any ideas? I am pretty much tapped and I don't want to put in any more money into things that possibly won't even fix my problem, especially since the condition of my misfire has changed since i replaced all these parts. Thanks.

 

have you checked the crankshaft position sensor?... Pull the dist. out and check the gear for wear on the teeth too...is the valve adj. correct? EGR valve cleaned? theres just so many thing associated with a misfire, been there i feel yer pain lol

 

if it were the crank sensor, wouldn't more of my cylinders be bad instead of just 3 and 6? i will check the egr this weekend when I pull out my intake manifold. aren't these hydraulic roller valves, so wouldn't the valves adjust themselves? plus my compression is consistent all around, so i don't know if valves are it. i hope it's not the distributor. Thanks for your input.

 

i would have to say ICM, or a ground of somesort on the block

 

is there anyway to test the icm and coil? I took it to auto zone and they said that they cannot test it for my blazer.

 

i had the same problem with mine 4 months ago. it did everything that you mentioned. i changed the crank sensor, and the problem has stopped. mine has been running great eversence

 

i read that the crank sensor was a tsb. Something about it hitting the reluctor coil. I will take it out and see if it has signs of that and test the sensor. Thanks.

 

Update: I have checked the crank sensor and it is getting good voltage and it is withing specs on the resistance of the actual sensor. Today I removed the lower intake gasket and it was destroyed. I think that it might have happened when it was being delivered to me. The engine over heated on the way to my house and it cracked the radiator and they ran it for a few miles while it was overheated to get it to my house. I checked my distributor and it had normal gear wear. Nothing out of the ordinary I think. It had some play when I rotated it, but thats for the mechanical advance, if I am not mistaken. It also had up vertical play, but I heard that that is normal as well. It had very minimal axial play when I checked it before I removed it from the engine. I think it was a tolerable amount, so I can rule out the distributor. I ran out of light for the day, so I covered everything up and will finish it up tomorrow. Hopefully that will fix my problem. I did however, have one question. The intake manifold has 4 water jackets. 2 at the front and two at the back. My question is to ask if the back two water jacket ports are supposed to be plugged? I don't know if they are meant to be like that, but I believe that it's not because it looks like its build up because its rough and is brown in color. If it is not supposed to be there, if I try to break it loose, will I run the risk of damaging the intake manifold? Thanks a lot guys. Hopefully this will finally get my baby running right!

Edit: I also noticed on the lower intake manifold that the second bolt hole closest to the passenger compartment on the left side of the engine (1,3,5 cylinders) has a slit in it. I am not sure if this is how it is or if the bolt hole needs to be closed. It does not look broken to me. It looks like its got a clean surface and that it was machined that way. If it is in fact broken, will this affect it when I tighten everything back down and possibly cause a leak? It is bolt hole number 2 when you follow the tightening sequence. I am using the Haynes book for the reference of the tightening sequence. Thanks once again.