Still looks like silicone to me, was it?

 

It was some type of sealant but I have no idea what it actually was. So weird. The rough idle is slightly there still but it isn't like a misfire any longer. It just feels like a vehicle that maybe has 180k on it? Or maybe the fuel injector is starting to get worse? Don't get me wrong it's driving like a dream. I feel like I got a ton of low end back without a vacuum leak. But I still want that thing perfectly smooth. Should I maybe take a fuel injector on my trip just in case? Cheap insurance?
'

 

Is there a reason you're thinking fuel injector? I ask because I'm at 220k and it idles just like it did new. I've put some cheap gas through it through the years and it's been a looooong while since I've done the Mopar combustion chamber cleaner. It's on the list, just not high priority.

 

It shakes the entire vehicle slightly when it does it. Smooth as can be driving. Then sitting at traffic light after about 10 seconds it will start. Just like a misfire but I also felt something similar the first time I got bank 2 cat code.

 

Did you try injector cleaner? Premium fuel at Shell is supposed to have good cleaning additives as well. Have the symptoms changed in way that appears related to repairs, or even something like temperature? Any codes?

 

It's weird. No codes. I'm thinking also a possible sensor starting to fail like the CPS or CAM. I have extra of those on board since I replaced them before they failed. I feel that the CPS should be standard practice for everyone if it will completely leave you stranded. I guess that also holds true for CAM.

 

Ran a can of sea foam with no change at all. The throttle body helped greatly but the pitch of it is deeper like it is in the engine more without the vacuum leak. Lets talk sensors here for a second. Which ones control throttle or idle? If they are like $10-$20 sensors I'll just put them in and take the spares with me to have on board. MAP Sensor? IAC? Just throwing shots in the dark out there. But I have a CAM, CPS and Wheel speed sensor on board.

 

There's a MAP but I'd venture to say the throttle position sensor is going to be what you're looking for and it's within the throttle body unit and those aren't cheap to carry around. The MAP was cheap but I didn't notice any performance change after replacing it (after falsely suspecting it to be bad).

 

There's no separate IAC (idle air control) on these engines, the throttle plate is the only air control. As Karl mentioned, the position sensor is within the throttle body assembly.

I carry the cam and crank position sensors, plus the map (manifold absolute pressure) sensor. I doubt it's any of these, but the map is cheap at NAPA, worth carrying, and takes 5 minutes to replace.

Leave the battery disconnected for a few minutes so it clears the adaptive settings in the PCM with a new map sensor. The fuel trims will end up slightly different since there will always be slight differences between sensors.

Seafoam has its merits, but it's not that good as an injector cleaner. Suggest using Gumout brand or something similar in the snake-oil isle at NAPA.

The PCV valve might be the culprit, especially if it comes out of it's o-ring groove -- which happened to mine. It was literally loose and probably was lifting up into the rubber hose, seating on the tapered part above the PCV during idle and deceleration. Since the PCV is essentially a metered vacuum leak, it needs to be a consistent orifice at the manifold pressure during idle. Maybe the o-ring was too soft, I have a hard time believing it didn't get it seated right during installation. In any case, when the o-ring is seated correctly, the PCV valve moves easily a small amount. If it's tight, it's either not in far enough or it's pressed too far in. Spent some time verifying this in case it happened again... When pressing it in with a socket, go a little at a time, checking that it's going in straight, and if the o-ring feels like it's slid into the groove.

Does the idle shake happen in neutral/park, or only in drive? Check that next time if you haven't already. If it's good in neutral/park, try reverse.

 

If you get to where you suspect the throttle position sensor is flaky at idle position, and want to try swapping out the throttle body -- I've got a known-good spare in the shop. Can mail it down to you for a test.