Rough idle mis fire (1 Viewer)

[maddss]

94 LC 225k. Has a rough idle, runs rough and has a stumble as you drive. I installed new NGK wires, Denso plugs and factory cap and rotor. Also clean the throttlebody. Still have the same rough idle and stumbling. One at a time I removed each spark plug boot to determine which cylinder was misfiring. #6 Cylinder is the issue. I swapped out a new spark plug and it still has the same problem.Any thoughts on how to help correct the problem

 

[george_tlc]

Could also be a dead injector on #6, that was the case on my '97... Or could be the infamous shorting cable bundle against the EGR...

cheers,
george.

 

[maddss]

@george_tlc How hard is the #6 injector to remove ?

 

[Tools R Us]

First, is the injector firing? Listen with a stethoscope. If it's an electrical problem, removing the injector isn't likely to be helpful.

 

[george_tlc]

You can check for dead injector with a meter. CAREFULLY remove the connector/plug and ohm out the injector, should be around 13 ohms. As toolrus mentions, you can also put a mechanic's stethoscope on it and you should hear it clicking on each injection cycle.

How's the harness along the EGR?

You can see my 'adventure' -> Injector Service

cheers,
george.

 

[maddss]

@george_tlc Just got to the back #6 injector While in the motor it was reading at 40omhs On the bench it’s at 20omhs. All other are st 14ohms.

 

[george_tlc]

Well, sounds like it's out of spec. My dead one was open circuit so clearly faulty

Given the rest of yours read 14 ohms and the 'bad' one is at 20 ohms, I'd highly suspect that it has issues (versus your meter reading wrong...).

cheers,
george.