Ooops. Yeah, that's "Random Cylinder Misfire"...... Won't find that one on an OBDI.

 

I took the truck back to the body shop last night. It would idle at about 100 rpm, but other than that it ran just fine. No check engine light, no mis-firing. I will keep this thread updated for any ignition system changes we make. Thanks for all your help!

 

Is the IAC not working???

 

I'm not sure, I think the computer just needs some more time to adjust everything. The IAC and TP sensor were also donated items that might as well be replaced, hopefully they will help with the choking issue once it gets warmed up. I'm not sure what to call it, it doesn't mis-fire, but seems to not idle as well once it is warm. That has been going on for a couple of years, and gets really annoying when pulling a trailer from a stop. You have to give it a little more gas to get the rpms above 1800 before releasing the clutch.

 

The computer should learn idle right quick. Would be interesting to see what the PCM sees for data.....

 

I replaced all the spark plugs and put copper plugs in. Of course I'm an idiot and put a rubber gasket on the throttle body in upside down, thus blocking the idle air port. The truck is running great now. That is until it gets up to full operating temperature. It seems that as soon as the thermostat opens it starts misfiring and the check engine light comes on. I can't check the code because the light goes away as soon as you turn it off and back on. I still haven't had a lot of time to work on it, so haven't figured it out yet. It does have new cats and a new muffler. Not sure how it passed emissions, the old cats were so disintegrated that they were hollow.

 

It should store the code in any event. Need to know what that's all about, though, I suspect the coolant temp sensor is having fits.

How old are your O2 sensors??

 

I completely forgot to have the exhaust guys put in the new O2 sensors. I have the new ones, I just need to put them in. I believe I also have a coolant temp sensor. The truck is primed and ready to paint. Hopefully the body shop will be able to get it finished in the next week or two and then I will really be able to dive into this project. The goal is to have it done by Memorial Day, so I don't have a ton of time left. Thanks for your help. I will try to check the code the next time I have access to the truck.

 

Think I would have been more inclined to make it run/drive nice, before getting paint. I HATE working on vehicles with "new" paintjobs. They inevitably get scratched. I wish you better luck.

 

Just a brief update. We got the truck back from the body shop and revealed it on Memorial Day but it still had random misfiring issues. The o2 sensors have also been replaced. We switched out the coil packs and that didn't fix it, so now the truck is at the auto shop. They say that everything looks good with the wiring and installation and they aren't sure why it isn't working. I wonder if the ECM doesn't work with it. It's still just giving a code 43. After driving it more I noticed the misfire can happen at anytime, could be a minute into the drive or 10 minutes in. The shop says that everyone they have contacted say that the viper coil packs are compatible with the mopar engine, but wont give a reason beyond "They aren't the same vehicle." I've heard of people converting Jeep Cherokees to use the viper 6 pack for the 4.0 inline 6. Not sure why this isn't working, but hopefully the shop gets a response from the engineers they claim they are talking with.