I thought I'd share this for anyone interested in an easy improvement to the Journey. I smoothed out the air passage from before the snorkel to the throttle body and it seems to have given me a smoother/quieter engine, better mpg and better shifting.
Here is what I've done in case you want to give it a try.
1. The top section of plastic that integrates into the front grill along with the underside of the hood, are the surfaces which the air first passes over in route to the air intake snorkel. The is sealed between the two surfaces by rubber seals on the hood so you'd only address the area within the rubber seals. I smoothed out those surfaces by applying auto wrap film to them. The factory plastic is fairly smooth but nothing in comparison to an auto wrap. You'd need to read up on auto wrap and use a blow dryer to get the wrap pliable to the surfaces.
2. To apply the wrap film under the hood, I first removed the rubber seal which sits in front of the snorkel opening when the hood is down. It prevents direct air flow into the mouth so removing it immediate give better air flow. My guess is that it was meant to prevent objects from entering the air filter housing so after I removed the rubber, I drove the car for about a week and in heavy rain to see if any water or objects would end up in the air filter housing. I didn't get anything into my air box and I drove it mostly on city streets. During a heavy rain, I checked out under the hood and found a few drops near the inlet but other than that, totally dry. I've checked it after a lot more driving and still nothing in the air filter box.
3. The film wrap on the top of the grill covers everything forward of the snorkel and ends inside the snorkel at the bump up of the snorkel. It goes over an ill fitting joint of the snorkel and grill section and smooths them out. Before I wrapped, I smoothed out that two matting surfaces with a file, a razor and sand paper so that it's as level a surface possible between the two. Before I wrapped this, I also tightened up the joint. That part is mentioned at #4.
4. I added film to the top underside of the air inlet snorkel. I removed the plastic push pin running through the top of snorkel. The pin connects the two sections of plastic but it's sloppy fit. I then pulled the snorkel up closer for a tighter fitting joint between the two, put some gorilla glue under the joint and drove a small screw to bind them until the glue dried. The film I applied went back about 3" into the mouth, enough to cover the old screw hole and the push pin hole. The film also wrapped down the sides into a U shape.
5. All of the work I did where I was using auto wrap, I tried to first remove any rough edges to create very smooth and flat surfaces with. If you feel around in the snorkel you will find rough spots and areas that can be improved from what came out of the factory.
6.After everything was film wrapped, I ran a cloth through the snorkel into the air filter housing to remove any grime and did the same wipe down inside the air filter housing. In the air box, you will also find rough edges on the surface shortly before the air exits the box toward the throttle body. I used mostly a razor on those rough spots, maybe some fine sandpaper as well.
The section of plastic between the air filter housing and the throttle body also has some mfg. imperfections and rough edges. I used a razor to clean those up as well.
When finished, I had a very smooth passageway for air travel. I don't know the physics of it but it seems like that lack of turbulence somehow made the computer read the air flow differently and improved transmission shifts and the 2nd to 3rd hesitation shift. It also improved higher speed kick downs. The entire engine seems quieter so my guess is some of the acceleration noise was partly rough air noise. The engine feels much smoother during acceleration from this as well, mostly in 3rd gear. I know this sounds like a stretch. I was only looking for improved power so these results were a surprise to me and it's not as if I found the result I was looking for. It came out of left field.
I hope this is info someone can use and let me hear if it works for you. If anyone finds the interest, I'll try to post photo's.