Problems after deck plate mod. Please help!

So I did the deck plate mod about 2 months ago. Used sensor safe silicon and reset the ecu afterwards. I have a 2000 3rz.I have driven plenty of miles for the ecu to get adjusted.
My problem is, when I have the deck plate open my truck seems to not want to shift at times when it should be shifting. For example; today I was driving at approx. 40mph on a straight road and I tried to punch the accelerator to pass a vehicle and rpms stayed at about 3500rpm and my auto tranny would not shift down. I was having a similar problem driving over the pass. My truck was stalling out at 65mph and would not shift down to accelerate.
When the deck plate is closed everything seems back to normal. Can somebody give me some insight please?!

 

Look how close that vacuum line is to the DPM try a smaller deck plate. my guess is that you're losing vacuum and it's messing with the ECU/TCU

 

I'm not sure how I could use a smaller deck plate without getting a new air box. Do you think that adding some sort of filtering material over the deck plate opening would do a sufficient enough job of restricting some of that extra air?

 

get a piece of plexiglass and make a ring that has a 1" smaller diameter opening than you currently have. That's where I would start at least.

 

Why is the deckplate on the side of your airbox and not the front? Your probably getting a lot of hot air from the engine bay.

 

Not sure if this is relevant but when I changed the muffler only to a Magnaflow on my 06 Tundra I had similar results. The truck felt like it wanted to hold a gear longer and wouldn't shift. It didn't do it all the time it was usually when I was going down a hill. It DID NOT have any airbox mods.

 

It's a vacuum issue I can almost guarantee it.

 

That was my question as well. If it were mine and I was dead set on keeping the deckplate mod, I'd cut a new hole in the front and seal that side plate and try it out. Me personally, I've sealed my plate and left it as the open plate just didn't work as well as I wanted. It gives me a bit more power on the interstate but it also decreases my mpg's but 2 or 3, plus it doesn't pull as well down low with the plate open.

 

+1. Check all your vaccuum hoses/lines and see if that gets you anywhere.

 

Can someone tell me what the function of the hose on the top if my air box is? Its not labeled in the vacuum diagram on the hood. This is the vacuum hose your allow talking about right??? @_@ thanks for the help!

 

...cause it's not a vacuum hose. So all that speculation implodes. I do believe it's the PCV air supply - it is simply drawing air from above the filter so that there is not a separate PCV air filter. Half an inch above the air filter there isn't much "vacuum" to lose, unless the air filter is plugged. Vacuum tends to be on the other side of the throttle plate, last I checked.

Dunno about the not running/shifting right, but I doubt it has squat to do with that hose. Perhaps you trained the ECU with the plate in, and it doesn't know what to do with the plate open? I was just reading through posts looking for what is this "deck plate mod" where the search function has not yielded the root post yet, so I've been gathering impressions form other posts like this one.

Can't check the hose on my truck since it's spending quality time with my mechanic today, but that's my recollection of what it does. Could also be something like air injection, but I don't recall that we have that at this vintage - at least not with the pump for it. In any case I'm sure there's no vacuum to speak of on it, given where it is.