Ok this is the random missfire revisit.

About a year ago i was having some issues with random missfire when cold. So the first thing I did was cap roter( ac delco) plugs and wires (ac delco). Still had the same problem, So than i replaced the icm ( ignition control moduel) still having problem. Replaced the ignition coil, same problem. Replaced the sensor on the distrubutor. same problem.

so I red up on the subject and replaced the distributor drive gear.This solved the problem, last week this random miss started up again. but this time with a twist. At WOT it will miss for a second and than it will smooth back out.

So tonight I pulled the distrubutor and the gear looked a little worn so i replaced it. took it for a test drive and its still doing it.

This was a week ago, today i replaced the spider with the newer style mpi unit. Still having the same issues.




Vid of the miss

Random Missfire - YouTube

 

I am having the same damn problem. Mine sputters/ hesitates alot passing 2k rpm. But only sometimes. I just got done reading about egr valve cleaning. Try it bro. Also clean your maf sensor. Use the search feature. Write up with pictures will come up. Type in how to clean egr valve. and how to clean maf sensor. Great stuff. Im doing mine on my day off.

 

And dam you run your truck pretty hard. It's not a revv hard Honda.

 

I cleaned the egr a few months ago same with the maf. Also I dont drive like that all the time I was just demonstrating how it misfires.

 

When you replaced to new spark plug wires did you put that one special grease on both ends. The dist. End and the plug end?

 

I beleive so, I changed them out a year ago so its hard to say.

 

How did you set your timing? 'In the old days', WOT hesitation and random misses were symptom of timing problems.

Not to say that's it... there's all sorts of reasons for it and not just ignition, but it sure helps to know timing is dead-on.
BTW ...you do know the PCM detects misfires with the Crank sensor, not ignition circuits, right?.

 

The timing was set a year ago buy having the #1 pistion at tdc, than having the rotor pointing at the #1 spark plug wire. And the distributor was set back in the same position when I installed the new gear about a week ago.

And I checked the fuel pressuer and its at 60 at idle and 65 when I crack the throtle.
replaced the spark plug wires and nothing has changed.
When I get paid I will do cap and roter again and If it still dose it than il check the plugs. And I know its not the maf cause I unplugged it and took it for a ride and it still missed. I am at whits end with this effing thing.

 

bump.

 

Tested fuel pressure while driving, sitting at 60 while crusing. at wot its just under 70 psi. no fluctuation when it starts missing. Also replaced coil and that solved nothing.