Help with cylinder 6 misfire (1 Viewer)

[Dog in Da Cruiser]

Hi everyone, a couple days ago while driving home I got a few codes thrown at me. I got a P0130 first and then right after a P0306 or a cylinder 6 misfire code. I managed to limp the cruiser home but there was definitely a misfire you could feel while accelerating or at idle it would stumble.
I did some research and found out that the P0130 is for the upstream o2 sensor, I ended up replacing it with an OEM one which fixed the P0130 code but I am still getting a misfire and a P0306 code.

Here are a few things that have been replaced in the last 750 miles that could be related
Distributor assembly
Distributor cap
Rotor
Spark plugs
Spark plug wires
Upstream o2 sensor

As far as I can tell there is no water on the oil fill cap or the oil dipstick, and the vehicle does not seem to be consuming coolant. There are a couple threads on the P0306 code that I am currently reading up on but Im wondering if someone could tell me why I got both of these codes (P0130 & P0306) within a few seconds of each other, unless it is just a bad coincidence.

It also might be worth noting that the EGR has been deleted.

Thank you, any advice is appreciated.

 

[Fj80oregon]

Did you check if your #6 injector is working? When you say egr is deleted do you mean completely like the egr pipe is gone and blocked off? You can listen to your injectors with a long piece of metal like a 1/4 or 3/8 socket extension. Or a mechanic stethoscope works the best you should hear the injectors clicking/pulsing.

 

[Dog in Da Cruiser]

Did you check if your #6 injector is working? When you say egr is deleted do you mean completely like the egr pipe is gone and blocked off? You can listen to your injectors with a long piece of metal like a 1/4 or 3/8 socket extension. Or a mechanic stethoscope works the best you should hear the injectors clicking/pulsing.

Yes, the EGR and all the related pipes are gone and blocked off, I wasn't even thinking of injectors and I will try and see if i can hear them fire.

 

[Dog in Da Cruiser]

Did you check if your #6 injector is working? When you say egr is deleted do you mean completely like the egr pipe is gone and blocked off? You can listen to your injectors with a long piece of metal like a 1/4 or 3/8 socket extension. Or a mechanic stethoscope works the best you should hear the injectors clicking/pulsing.

I just checked and as far as I can tell the #6 injector is firing at the same rate as the other that I could listen too.

Im not sure if its worth noting but the engine only seems to misfire when there is some sort of load on it, for example when its in neutral there doesn't seem to be a stumble in the idle at all, but when I shift into drive I get a stumble and rough idle.

 

[ajax1]

What plug wires? Wire harness good?

 

[jfz80]

Def sounds similar to crispy wiring in the main harness where it (used to) contact egr pipe. Putting under load torques motor just enough to distort that bundle and expose a short.

 

[logicbyondreaso]

Wiring at the EGR pipe needs to be looked at. I have worked on a number of 80's with these symptoms. Under load the engine torques and stresses the harness a small amount. Enough to disrupt a failing connection.