Fuel Pump or Air injection?

Hey, I need help trying to diagnose what may be wrong with my truck. I drive a 2005 2WD 2.7L Tacoma, and it’s been absolutely great! About a month and a half ago though I started having trouble getting my truck started. Would turn over just fine, but wouldn’t actually start, and it got to the point where I couldn’t reliably get it started so I took it to the mechanic and they said my truck was throwing P0418, P2440, P2441, and P2445 (secondary air injection issues). My truck has thrown these codes though for about a year and a half, I hit a deer and some stuff got bent up and codes just never disappeared after the fix. I believe the issue is my fuel pump though as my truck gets REALLY bad when my fuel is low. Symptoms are hard to start, engine lacks power on low end, and sluggish overall. I really believe it’s the fuel pump but I wanted more knowledgeable opinions! Thanks!

 

Also if it is the air injection, I know there is a bypass kit for that, so would that be the best way to fix it?

 

Secondary Air Injection has nothing to do with starting, all it is there for is to help the catyletic converters come up to temp faster.

Sounds more like a fueling issue, I'd get a fuel pressure gauge and check fuel pressure.

You will need one that tees into the line going to the engine like the one below.

$31 BETOOLL Fuel Pressure Test Kit 0-100PSI with 9.497.896.30 Fuel Line Fittings

https://www.amazon.com/dp/B07LF26ZTJ

 

That’s what I was thinking as well, mechanic was gonna try to rip me a new one for 1500$ to do a whole secondary air injection fix

 

But in your original post, you said

Was the SAI fixed or was it not fixed - though I agree with @Dm93 that the SAI only comes in to play AFTER the car has already started to inject exhaust gases.

 

SAI malfunction will cause limp mode which feels like low power, no fuel etc.

 

I think DM93 brought that up because has starting issued even before it starts missing, so when you combine the difficulty starting WITH the miss and low power, it doesn't point the the SAI.

THOUGH, I suppose if the SAI was leaking and pulling air from the exhaust system at startup, it would be like a massive air leak and therefore difficulty in starting.

 

I wanna say it’s not limp mode, those codes have thrown ever since I’ve had the truck almost and it’s only been a recent issue. It could be that I guess, but it wouldn’t explain the higher fuel level helping it run better

 

That code has thrown on my truck almost ever since I’ve had it, so it may have never been “fixed” technically, but yeah It wouldn’t make sense with the fuel level. I really do think it’s a fuel issue I just know the symptoms could point to SAI. Would the bypass kit be the best way to fix it if I have to go that route?

 

AFAIK this is only the case on the 4.0L, on the 2.7L SAIS codes don't cause limp mode.

The SAIS will not affect drivability in any way except v6 truck's will go into reduced engine power for a couple specific SAIS codes.
The SAIS runs only on a cold start for about 30 secs while the engine is in open loop, it injects fresh air into the exhaust to reduce cold start emissions and aid the catyletic converters in coming up to temp. It has nothing to do with fuel calculation and is not even used after the initial cold start or any subsequent startup at coolant temps higher than 140F.