2001 Dodge Dakota 3.9 P0301 p0303 p0305

Hi, Im pretty sure I know what this truck needs but I want to prove it before I replace the intake gaskets. Its got a history if Misfire codes all on back 1. The customer doesnt seem real concerned about it until its time to inspect it or when it runs bad. It has also had a cat replaced for p0420 1 year ago around 110k and a tune up (plugs cap rotor and wires ) at 120k. 2 months ago w 130k it was in for a bucking stalling issue along with lean codes and got o2 sensors and that problem and code is gone however it is setting mis codes, driver doesnt feel it or really even care but I do.
So tests performed ,All scan data seems right, injector balance. Scan data wide open throttle o2 stay rich , scoped Map, crank and cam signals actually swapped bank one injectors with bank 2 ( we new we were grasping for straws ) no change. I did in cylinder pressure cranking running snap and all look pretty normal though I think there is some back pressure but its equal on both sides so im ruling that out, this is only bank 1. Of course its subtle miss so its not missing during any of my testing which is frustrating. Freeze frame data showed 195 degrees, 1900 rpm 50mph 60 % load with equal trims both banks under +10% combined. Ill attach the pico captures, we can discuss them either way as I just now finally got a pico. Are overlays part of Pico6 software or do I need to get them someplace? Oh, I put a vacuum gauge in the dipstick tube and get zero vacuum at idle under load and snap test. Its speed density so my Maf logic isnt helping me prove its a vacuum leak
Anyway. All of the silver bullets are saying "just put intake gaskets on it" Move on with life. I just have to prove it to myself.
What a, missing? I know there is something. Thanks for your time I appreciate any direction.

Maybe I didn't look closely enough, but were your Pico captures say which bank they came from? There's definitely a difference bank-to-bank, but I'm not sure it accounts for your misfire. Do you have the throttle snap captures from both banks available?

When you checked crankcase vacuum at the dipstick tube, was that with the fresh air and vacuum hoses plugged? Just want to make sure your reading was valid. That may be nitpicking of me, as the freeze frame tends to point away from a vacuum leak as the problem, anyway.

Tyler,
Sorry I didnt get back to you much sooner, I thought I would get an email when someone replied to the post,
The first file # ending with a 1 was bank 1, the angry bank the file with 2 in the file name is bank 2. Yes I did snap throttle in both of them you will see the compression get much higher during that event, I should have added tps to make it more clear.

No I didnt close the pcv off when checking the crankcase vacuum. Might help if I do that. ( darn it )

No worries about the TPS, I think I didn't zoom out all the way when looking at bank two. :blush: I'll have another look later on today.

I asked about blocking off the PCV 'cause I've done the same thing. :lol: You'll know you got it sealed off when the gauge either shows pressure or vacuum. A good engine will build several PSI of pressure with everything blocked.

So I had another look at the bank two capture, and I'm still not sure the throttle snap is in there? :huh:

I'm not positive about the Pico overlays - I don't own one, I just have the software to review captures. I found the degree partitions, but couldn't get them to display 720 degrees. :lol: :blush: