Hey guys, I'm hoping I could get some much needed advice here. I recently repaired a Leaky lower intake manifold on my 1996 Blazer - 4.3L with 199.3K on it.
The repair went well thanks to the great articles found in this forum.
while I had everything torn apart I replaced plug wires, plugs, distributor and the rotor button. When replacing the rotor I made sure to mark it and replace it in the same configuration.
After I had everything back together the engine fired right up, took it for a spin, first things seemed normal, then a couple min of run time later the engine would hesitate when I would pull out and had an obvious miss. Turned out the #5 plug wire was haning loose. Replaced it but the engine hesitation is still there. Runs fine at idle, revs normally when in park or nutral but if you put it in drive it will hesitate when you accelerate and shows the obvious signs of a miss.

The only thing I can think of that is wrong are the plug gaps. My HANES manual called out the gap to be 0.045", I took the manuals word as correct and gaped them 0.045". When I replaced my upper fan shroud I then saw a spec on it that called the gap 0.060". Could this be my problem? plugs are a PITA to change in this vehicle, I think i'll go out and try to pull them and regap, meanwhile hopefully somone will share some of their thoughts.

Thank you in advance,
-Dustin

 

Have you checked all the vaccuum lines, EGR, PCV etc?

 

What brand of parts did you use for the cap/rotor? Some of the aftermarket parts have been known to have issues out of the box.

 

I used AC Delco Plugs, BWD Wires & Delco roter & Cap.

I pulled all the plugs and re-gapped to 0.060" I imediately noticed a significant difference. The hesitation was greatly reduced and the miss is gone all together. I still get the slightest hesitation when accellerating from being stoped, but that was present before even preforming the LIM repair.

So, bottom line - my engine definately did not like the 0.045" gap the Hanes Manual & owners manual suggest. 0.060" gap was the ticket.

Thanks for the advice.
-Dustin