It's usually most noticeable a moment before the 1st to 2nd shift. Just like a slight studder. It's crossing my mind to put new plugs in it, or just replace the coil for $34. (plugs "maybe" have 20k on them.) Pretty sure they are delco platinum; what I always use.


It is pretty subtle though; If I had not said anything, my wife probably would not notice it. But it does definitely pulse/shudder a little only on low / mild acceleration coming from a stop; and when cold.

 

gosh one would have to be with you to feel that. there are internet sites that outline how to test coil without buying a new one using a multimeter. Lastly if you replace the coil(forgot what year blazers) you may need to cut off the rivets to re-use the bracket that mounts the coil to intake. the new coil will have a bunch of screws and nuts. Something to think about.


You could take a timing light to each plug wire when running and visually inspect the pulse to see if you have any plug not receiving the same spark pattern.


Usually up there at that shift rpm I would guess transmission? I've gone through the whole shutter problem and learned with a transmission often the most one can do is a full fluid exchange and new filter.


if there are no misfire codes and no check engine lights. you could check short term fuel trim and long term for kicks just to see if engine is running rich or lean.


A fuel pressure test might be a good idea , forgot if you said you did that.


I recommend a tranny shop go for a ride and just make sure everything is ok? see if you can reproduce it on demand for them.

 

Does it feel like it is possibly missing a little? I know when all 6 cylinders start firing correctly during acceleration after they weren't a short time before it feels like you temporarily hit a turbo boost button, Like the motor all of a sudden wants to run better then toggles back. This should give you a MIL after a short while though if its enough to feel. Another possibility, with your defroster on or your AC on. If your compressor is short cycling you will feel a slight surge every time the compressor clutch disengages.

 

Trans has fresh fluid and new filter. I think it's a minor loss of power. Now that you mention the rivets; I may have changed the coil once already... I'll see if that has warranty.
I'm also going to give it a double dose of SeaFoam in the gas tank later today.

 

Sorry been crazy, you said you changed the cap, sometimes the plastic ears on the distributor will crack even if you don't over tighten them. Also there was a guy that had a problem he had trouble tracking down, he had changed cap and rotor and the rotor screws were a bit loose.

 

Noticed today when I geared down to 3 or 2 and holding constant speed it was a definite miss.
Anyways... utilized my limited lifetime warranty Wires, Cap & Rotor, and all is well.


I will note that: after removing the cap "again", both ears were broke off this time, so I gently screwed the new cap down and then used some zip ties to hold it tight. Seems pretty solid for a rigged up fix. I also noticed that the tube that goes into the backside of the large air intake tube and then into the passenger side valve cover was not pushed all the way down. It was in there, but when I pushed down it seemed to pop into the valve cover more securely.