Nope. Might just be showing up when the engine goes into closed loop. (starts paying attention to the O2 sensor.)

What kind of shape are you plug wires/cap/rotor in? How old is your coil? Original? How many miles on the truck?

In order to effectively eliminate the plugs as a possible cause, replace ALL of them.

 

I had the same problem (I had to pull exhaust manifolds due to exhaust leaks and of course broken bolts & studs) and after reviewing this particular thread I found that a few years back the dealership mismarked spark plug wires 5 & 8. I installed these two wrong and oops....It chugged really bad in OD and the check engine light came on. That did the trick though.

Thanks guys!

 

Good point! Open loop makes perfect sense. I know that I can retrieve all of my open and closed loop data on my Hemi wagon by data logging...is that an option with these trucks. Or how can he trick it into a constant open loop for testing?

 

Disconnect the pre-cat O2 sensor.

 

whats open and closed loop?

 

When the engine is cold, the computer runs it off from tables of preset values, that are 'in the ballpark' of correct mixture ratios and such. Once everything gets to some predetermined (by the programmers...) temp, the PCM will go into Closed loop, and the O2 sensor becomes one of THE most important sensors on the truck. That is what determines how the PCM adjusts fuel trim. If the O2 sensor lies..... you either get horrible gas mileage, or, the engine will run really lean, and ping, and miss......

 

ok, well I checked all plugs and all looked good, whats my next step, I even replaced (2) that I thought were not as good as the other but overall looking at the plugs and wires, they all looked good and somewhat fresh

 

Which two did you replace?

 

(2) drivers side rears

 

Hows your plenum look?