oh, no don't worry about the length. I am welcome to any and all replies, especially longer ones that go into depth of how it relates to my problem, like you did. Thanks a lot. I appreciate it. I will be pulling out my distributor this weekend.

 

brother, you're truck sounds like a carbon copy of the crap my '98 has been throwing out since Feb/Mar of this year. distributor looked fine when pulled, and i was convinced it was an electrical issue, not the lower intake gaskets 'til a couple of weeks ago.

i noticed that the tach wasn't dropping RPM's, it was raising RPM's (like a slipping trany perhaps?), and it feels like the lockup on the TC was engaging/disengaging rapidly, causing the "jerkyness" i experience (especially at start off, worse @ cold engine temps).
since i figured this was the trans on it's way out, i was content to just let it blow-figured it was gonna drop around the 21st of January next year........you know, the day it drops down to -40 degree weather.

since you mention pretty much the same issues, and that was your solution, i think i'll drop the $112 for a new distributor-'cause i sure as hell ain't gonna swap in the used spare i have after reading your reply.

thanks for the info and personal experience.

 

Update:

So my truck has just basically been sitting around ever since I have had it except to occasionally drive it to the shop to tinker with it. I just have not had to money to shell out anymore on this truck. I'm getting my tax return back the Friday before Valentine's Day so I am about to get back to work on this. This is where I am at and I want to know your insights.

Having done a complete tune up (cap, rotor, wire, and plugs twice), done the poppet nozzle conversion, changed out upper and lower intake manifold gaskets, and testing the coil and icm, and having great compression all around, I can only think of one final thing. The distributor itself. I have read TSB's to see of similar misfire problems and have read countless threads on here of P0300.

The TSB I read said that the distributor shaft can get rusty and cause the P0300. So I took off my distributor and checked in the shaft and it was red with rust. I started spinning the shaft and I could hear it squeal and it felt like it was very slightly getting caught up and was not spinning very freely. Considering I have ruled out just about everything else, this is the only thing left for me to replace, right?

I am not going through the dealer for a new distributor, they wanted to charge me $450 for one. I have looked around and found a store that is selling a brand NEW distributor for $80. It comes with everything including a cap and rotor and new cam sensor. Pretty sweet deal in my opinion. Now I have a question.

I know that if I replace this, I will have to do the relearn procedure due to the new Cam sensor. I however, do not have access to a Tech II scanner to do this. I have called around my local dealers and they are charging around $150 to do the relearn procedure. Considering I don't feel like spending more on this relearn than I do for the actual distributor, I was wondering if you guys know of anywhere that will do it for free or at least at a cheaper price.

Another thing was, is it absolutely necessary to do it and what will happen if I just drive it without doing the relearn? In addition, since there is nothing wrong with the cam sensor on the distributor I am going to replace, is it possible to just switch over the cam sensor to the new distributor, or will I have problems that way. Is that not recommended?

Whew, sorry for that short story, but I can see the light at the end of the tunnel. I am so close to getting my truck running and I am sad to see it just parked for the past few months. Hopefully I am on the final leg of getting this darned P0300 issue out of my life and start out fresh with my Blazer.

Thanks guys. As always, any advice is welcome and definitely appreciated.

 

as far as i know, there isn't a problem with swapping over your old cam sensor.

but i'm sure Kyle will either see/hear about this question, and offer up better/more accurate info regarding that.

try PMing him in a few days, if he hasn't offered up his opinion on this.

 

All right, thanks for that. That's what I wanted to hear. Music to my ears. I will PM him if he doesn't get around to reading this. Thanks again.

 

So I got my new distributor today. I swapped out the cam sensors, putting the old one on the new distributor. I pulled up on the freeway and made a good 20 mile trip and the SES light did not flash or come on once! Then things went downhill from there.

I let the truck sit for a while so I could grab a bite to eat and I went on another trip. This time the light came on and stayed on. Pulled off the freeway and drove for a while, then it went off. Went back on the freeway and the light started flashing. Went from a happy mood to crap in 20 in 3 seconds.

So, is there anything else that I missed? I ran out of solutions to stop this misfire. Plugs were changed out twice with Delco's, new plug wires, cap and rotor were replaced twice. All the intake gaskets were changed out. Compression is about 150 all the way around. Did the fuel injector conversion and just put in a brand new distributor. Coil was tested and I bought a new ICM today as well.

Could it be that the cam sensor can't compensate for the new distributor? They are not the same. The new one is noticeably heavier and fatter than the old distributor. If I spend the $120 to get the CASE relearn done on the new cam sensor, do you guys think that it might solve my problem?

If that doesn't do it, can you guys think of anything else that I might have possibly missed? This really has me stumped.

Thanks everyone.

 

If you replace the CMP, CKP, or distributor, you should do a CASE relearn.

If the distributor came with a new CMP sensor, I would use that one and see how things go.

It definitely sounds like the problem is occurring once the truck reaches closed loop operation.

On this new trip, did it act up or just turn on the CEL?

 

First time the light came on, it just stayed on. I had the code cleared and went back on the freeway and this time it just flashed because I was harming the cat, but after I slowed down, it stopped flashing and went away.

It's always done this from day one. With every thing that I do to it, I take it out for a spin on the freeway and the same thing happens every time.

3 and 6 always misfire a ton (thousands of times to date) and on a very, very, very rare occasion, 1 and 4 have misfired (maybe 20 times each).

I think it's the same cylinders still, but I won't know until Monday until I can get my hands on a scanner. I just wish the Genisys I use could do the relearn procedure. Kind of a bummer that the distributor only cost me $80 and the relearn is going to run me about $120 at the dealer with the possibility that it might not even work.

 

Have you done a compression test? Do you have access to a bore scope capable of getting through the spark plug hole?

 

Compression is about 150 all around. I might be able to get a bore scope. Not sure if the shop I go to has a bore scope or not.