Sounds like the TB not operating properly with the tune to me. Had some problem. It normally happened to me under downshifting from 4 to 3

 

I didn't see his boost gauge flickering when It was happening, I would expect to see that happen if the T-body was closing. that's weird OP...almost sounds in the video like its missing or back firing.

 

If that was the problem wouldn't the issue be consistent and non intermittent?

 

Tuner mentioned possibly water getting in the air box and getting to the MAF, but without the car we're just guessing. Could a wet MAF cause this? CAI is just your standard Airaid box and it appeared to be dry, but I didn't really look at that until a day later.

 

Yeah i doubt that. I drove around monday to and from downtown through some pretty high water with no issues...well other then my horn sounding like its under water now. Lol. I hate to say it but hopefully it comes back so you can get it diagnosed. Do you log data? If so you may want to keep your laptop running every time your driving, if it was a maf issue you would see it with hptuners.

 

Ay chance the weather conditions were different, i.e colder/denser when it happened? I've heard of the overboost protection needed to be tuned out. On a hot day you may not be tripping it with your pulley combo, but under the right circumstances it is making enough boost to trip it and it tries to dump some of the excess boost. Totally just guessing, but I know it needs to be turned off in the tune if you pulley up. I hope you find out what it is.

 

I had that happen. Ended up having a cracked insulator on the spark plug.

I have had a lot of miss / shuddering issues. Resolved them with plugs gapped to .028 and making sure that plug wires NEVER touch any metal.


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Looks more like a cutout then a misfire, I noticed it stays in boost the whole time. Maybe a fuel issue?

Pull plugs and check

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Op any updates?

 

Traveling right now and didn't get a chance to get it in the shop before I left, taking it in this week.

I've driven it a few more times since OP post and no problems, runs beautifully. I'll keep you updated.

 

Not only was the boost gauge dropping off when it did come back it looked like it was much higher then before it dropped off. Interesting.

 

I've never had a misfire shudder the load and rpm that much. And I've had some bad misses in the past.

Only thing that slightly resembled that was a head gasket failure but it was a bit different the way it acted so disregard.

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Prior to getting a custom tune I was getting really bad shuttering after downshifting from 6th to 4th. it would feel like the car was bucking with just a CAI and ported TB. I dont recall my boost gauge bouncing all over the place like this though. Since I have put all my mods on and got a custom tune it went away. Mike did mine remotely. I do have a slight issue at cruising speed but thats different then this.

 

Most of the things you guys have suggested as possibilities, wouldn't those be something I'd experience always instead of just that one day? I can't seem to recreate it.

 

If that day was cooler and the air was denser there is the possibility that may be causing a slight issue, best bet is to keep and eye on it, without logging its going to be hard to pin point. Even with the ability to log unless you understand all the variables I still find it difficult but then at least you have something to show people who are much smarter then me I wouldn't be surprised if your Torque management is kicking in, why? because thats my guess. lol

 

I can think of one thing that could cause this in heavy rain but not be repeatable later. Droplets of water hitting the MAF can cause its output to tank momentarily, and it's possible that this would cause the PCM to shut down things like boost. This is because the MAF works by using heated wires that are cooled by the passing air, and the output is determined by measuring the resistance. See
https://en.wikipedia.org/wiki/Mass_flow_sensor#Hot_wire_sensor_.28MAF.29

If a water droplet gets in the intake somehow, it would momentarily cool the wires and spike the measured air flow measurement.

Things I would check: stock or quality air cleaner box and element, no torn paper in the air cleaner element, no leaks in the air flow path between the air cleaner box and the throttle body, no leaks between the throttle body and the MAF.