Power loss, 2rz

I've done a bunch of work on my 04 2rz. Recently reinstalled the engine. It cranks and runs fine. But when I need to accelerate, the power is not there. I finally climbs to speed, but slower then what is normal. I had a similar situation a while back. New plugs and coil packs fixed that problem, so I don't think those components would fail this quickly. I wanted to scan the system. Although I own 2 scanners, I can't find either one
I carried up to AutoZone, for them to scan it. Although there are one or 2 codes active always on this truck, it didn't see that. What it did see was Idle air control valve. Could loss of vacuum at the IAC cause this? I question their analysis. It idles fine as far as I can tell, but what I am experiencing is power lose at acceleration.
Any thoughts or ideas?
Thanks.

 

check air filter, clean maf, clean/check tb, clean/check iacv. Buy a bluetooth obd scanner

 

My brain wants to give a smart a$$ remark about it being a 4 cylinder but I’m trying to hold back lol.

There are a lot of possibilities, what yotagang said is a great place to start. Especially cleaning the throttle body.

 

My 3RZ did this. Clogged cat. Melts and destroyed my EGR system.

 

Why was the engine out?

 

PO505 code?

This has a drive by wire throttle body??

Corrosion or cold temperatures causing the signal to degrade to the ECM ??

A vacuum leak at the IAC would cause a constant high idle .

Maybe it is not quite as fast to accelerate as you remember

 

I got a really stupid question for you......

with what you know.....could you of set everything on a 6 lug frame instead of what you did....
get rid of the coil buckets.....

Thought never occurred to me until a thread today popped up......

Have any ideal what difference would be except for hard line braze-ons.......
you are the coil bucket expert here.......

 

As far as your power.....you need to be able to watch live data....
look closely at the fuel trims......that might point you in the right direction......

un/fortunately the ecm tries to cover for a lot of sins....some things have to be way off before a code is thrown......

What about tranny......could it be your torque convertor starting to slip.......


I have 2rz with AT......and low end throttle response on the throttle body is terrible.....

I bought a TB extender from LCE to deal with this......that one day may get around to installing it....

 

Yea. I need to find one of my 2 missing hand held scanners.
I remembered there is one wire that never got put back. It is on the left side of the engine, low and to the front.
A vacuum hose makes perfect sense. Everything was removed when the engine was taken out. I am sure I am dealing with some stupid overlooked item.
When I accelerate through the gears, there is a sweet spot. It is the only spot that gets the engine to accelerate. The pre-rebuild set up would just go faster as you pushed down on the petal. That has changed. It runs. And that's a beautiful thing. Its the last few inches of a multi mile trip.

 

Yes

You can read about it here
https://www.tacomaworld.com/threads/04-coil-spring-bucket-graft.745614/#post-26553633

 

Here is a couple of pictures of how the Idle air control valve vacuum is routed. Can one of you'll look at this to see if it looks right? It goes back to a box mounted on the left inside fender well. What is that box and what does it do? Could it be bad? Check the 2nd pic, to see this box.
It is running a bit better now. After sitting up for a year and a half, it is good to run some fresh gas through it. The old gas is, well, old gas.
At some point I may try swapping the Idle air control valve, or even the entire intake off of the donor truck. It is a luxury to have duplicate spares I can swap to isolate bad component. But I would rather fix it with the "original to that truck" parts.

 

https://www.tacomaworld.com/threads/what-is-this-connector.788983/#post-28242889

you need a 2003/2004 engine component expert...

 

Idle air control (IAC) does nothing except control idle. It will have no effect on acceleration at all.
Your second photo there is the evap canister closed valve, gray connector. It should be routed to the air cleaner. The other valve is the evap purge valve, which should go to manifold vacuum

 

I don't see the IAC on the diagram. I ran across that when researching this issue. If both these hoses need to go to the IAC, but are going to air cleaner and canaster, then both are wrong. Right? Clear as mud.

 

IAC is bolted to the throttle body. It doesn’t have any vacuum lines

 

Iac has fluid inlet and another outlet.........along a big air supply tube from upstream air intake system........

and one electrical connector....


IAC has two functions........

1st one is allow idle even when there is no foot on the gas pedal.....
throttle body ......not a carburetor.......no fast/slow idle.....

Second function.....hot water comes off the heater coil water lines.....thru the the egr valve then thru the iac....
this prewarms the carburetor..........crazy japs.......prevents ice ups under rare freezing conditions........like ice divers special regulators.....

 

I'm going to need to go back an reinvestigate.
Good info, Thanks guys.
I'll let you know what I find.