Slight Hesitation on Startup

Hey all, having a slight hesitation on start in my '11 (4.0L), wanted to throw a few questions out there to the group as I'm not having much luck finding the answers I'm looking for.

Do 2nd gens have a check valve or any type of device in the fuel system that is supposed to hold pressure while the engine is off? The symptoms i'm having are eerily similar to issues i've had with old XJ's with the failed check valve that would lose fuel pressure after sitting and require a few pump primes before it would start normally. It's not bad now but I wanna get ahead of it before something dies on me and it leaves me sitting somewhere.

The issue: Most of the time on starts (mostly cold, after overnight sits) i've started noticing an extra crank or two before my truck fires up. It varies occasionally, with no rhyme or reason that i've identified, sometimes it'll sound a little more stumbly for the crank/first couple cycles and other times it is just a normal crank sound but just an extra crank or two. Runs fine once it starts up, and drives normally. Something additional to note, most times when i disconnect the battery for extended periods of time, the first restart will be exceptionally stumbly and it has started up, ran poorly for a few seconds, and then stalled out on me a few times. first few restarts only, and goes away after letting it idle and relearn, I always chalked this up to the adaptives being reset and just needing to be learned back in.

Recent relevant work, <5k miles ago: (this issue was present in some form before any of this work was done, just adding for context)
- replaced all 6 spark plugs with OEM toyota plugs. I didn't check the gap but assumed (hopefully correctly) OEM would be gapped correctly.
-cleaned MAF and throttle body
-replaced the battery


I've got a kit to check fuel pressure today with the tee fitting, and i'm also going to check the engine off hold pressure per post 4 here (Not OP instructions) Gonna see what that tells me and go from there.
https://www.tacomaworld.com/threads/how-to-check-fuel-pressure-w-pics.445975/#:~:text=First you need to pop,spray much fuel when removed.

 

I'm thinking this is normal... Mine does the same and has for many years. I think I recall seeing some old threads about it that probably explain more.

 

It’s a rare occasion to find new plugs gapped to specification. I like to center, then gap.

Check the air filter. If you have a OBD scanner check that. You could also try disconnecting the battery or use the OBD erase codes function.

 

Air filter looks OK, looks like it's been replaced in the last few years but i cleaned it up anyway recently. Nothing on OBD as far as active or stored codes and none of the fueling or O2 adaptives are learning anything crazy that I can see, my scanner doesn't capture every adaptive though but hits the big ones.

Still haven't got outside to check fuel pressure, it's been cold af which has been discouraging me...lol. but when i do i'll pull a plug or two and check the gaps.

 

Sounds normal to me. Especially in the winter when the temperature gets down low.

As for the pressure. Yes.
It should hold pressure. I forget actual psi. But I it is like 25 psi after so many minutes. Normal operating pressure is around 41-43 psi or so.

 

Turn the sensor 180' and see if it fits.
If it does, they sold you the sensor for the wrong side.

 

Wrong thread?

 

yeah.

 

Got around to checking fuel pressure today and am pretty confident ruling that out.

Held rock solid between 40-41psi the whole time, cranking, idling, revving. After turning the engine off it held 36 very solid for the 5 mins or so, well above the 21 psi pass/fail.

One thing to note like I mentioned above. On the first restart after disconnecting the battery, it will fire up and run smooth for about a second or two and then just die. No sputtering or poor running like i thought but just runs and then shuts off almost as if keyed off. Immediate restart has no issues and stays running. Wierd...maybe something with the throttle or idle air control?

I'm not so majorly concerned that I'm gonna tear the whole truck apart but I'll probably keep digging at this, not willing to chalk it up to 100% old age just yet. It does make me feel better knowing that the fuel pump seems to be fine and that it won't leave me stranded with no fuel pressure one day. Little victories.

 

The truck stalling after disconnecting the battery is normal.
A lot of guys have that issue, and have reported it here.

Oddly enough, Mine has never done it.

 

Do you keep your throttle pretty shiny clean? lol. A lot of what I read is due to the reset of throttle adaptives, which 100% makes sense, but that should go away with a freshly cleaned throttle and reset so I'll tear that apart and give it another good cleaning.

 

Nope. Never cleaned my throttle body.
I have almost 170k on my truck. Never touched it.

I don’t fix things that aren’t broke.

 

huh, fair enough, can't blame you there...well I'll post here if I come to a resolution on this. I've got some other things that I should probably prioritize first but a throttle clean is an easy, feel-good accomplishment type job and it's nice and warm out so we'll see. haha

 

The Tacoma is easy enough to clean.
My brother cleaned his TB on his Chevy 1500 w/5.3 engine. Took a damn scan tool to relearn the TP.

There was a time when I used to be more “proactive” on the little maintenance stuff. But now I’m “older” and lazy and just don’t want to do it. Plus, I’ve seen my share of “fix it until it’s broke”. I’m leaving stuff alone until I have a problem.

 

I'm at about 157,000 miles now. I cleaned mine about 20k ago and it was not overly fruitful. It wasn't really dirty and made no noticeable difference.
I'm not saying don't do it, but I don't ever really see where it helps many folks on here.

 

I wouldn't even think about it. You're describing how every vehicle I've ever owned behaves.

 

Same. Only done it a few times cause I hate resetting my radio presets, but never had an issue after.

Cleaned my TB and MAF maybe twice over my 80k mi of ownership