4.0 odd starting issue

True I just texted a buddy and he actually has one unsure if he will be able to help me with it tomorrow he is working on a old Honda interceptor atm but at least I know someone that now has one

 

Another thing that I just thought of but probably not a big contender is a possible small vacuum leak.

Something like a small vacuum hose that when relaxed after the truck has been sitting a while allows too much air in creating a lean situation just long enough to backfire as well as kill the engine. Then that hose gets sucked tight to its nipple and stays put for a while.

It's a long shot for sure, but just another free check by gently wiggling all the vacuum hoses around the engine bay while drinking your favorite barley pop.

 

Ya I’ll be checking lots of things haha I hate trying to find issues I like it when things just break because then I know what’s wrong lmao

like my little civic decided it no longer needs gears 1,3,5 or the oil in the trans I know what’s wrong with it lmao

 

Sounded like you’re planning to do the plugs. If you’re going to an auto parts store, you could ask them to check and clear the error codes, I think they should do it for free.

I know it’s been beaten to death, but a battery brush is cheap, you should get one, brush the terminals and posts.

Disconnecting the battery and clearing the error codes, either clears the whatever so the ecu will relearn once you start it again. It’ll run different for a bit until it does.

 

Buddy of mine checked the fuel trims and the truck is running rich he has a screenshot of it so when he sends it to me I’ll
Show you

Long term
bank 1 -4.7%
Bank 2 was -9%
Short term
Bank 1 -13%
Bank 2 -18%

 

You have a fueling issue on both banks. Just as I suspected. You'll need to check fuel pressure. And my money says it's your fuel pump. The chances that both of your AFR sensors are bad is pretty slim, but still never outside the scope of possibility.

 

Wouldn’t think it’s an injector issue?

 

Could be, you could have the exact same issue this other 2015 that I diagnosed a year or two ago had. It was pretty intense. The fuel pump was failing and because of it, it wiped out the fuel injectors with it, but the injectors were failing harder than the pump at initial diagnose and so we had to replace those first. The pump was caught after because it was causing the fuel trims to intermittently spike at idle.

It was a tough diagnose.

Check what I suggested previously and then go from there. No need to do triple bypass heart surgery first if it's not even required.

 

I gotcha and I agree I was just wondering and askin lol

but ya so what we noticed with the trims is in town driving, idle, and coasting it will spike but highway under load is fine

here is a pic of the fuel trims btw

 

All signs to me point to the pump. It's likely it has an inability to keep up with low fuel demand but once the truck gets going and demands more fuel it can keep up just fine. And even then, fine is a marginal thing because bank 1 is still past what normal values need to be.

You have ruled out the MAF correct?

If you have, check fuel pressure.

 

I have not ruled out the maf I need to clean it before I can rule that out

 

Cleaning a MAF will do nothing if it has lost it's calibration, which at your mileage is a very real possibility.

Usually the most common MAF failures to me display in the high 20's to 30's as far as fuel trims go, but given that you are lower than that, I'm almost positive it is not that. That is not to say, however, that your MAF is indeed not failing and emanating its failure in a lesser way than I have usually seen it.

The issue is both of your banks are being affected more so when air and fuel demand is low (idle) so whatever is causing that needs to be something that affects the delivery of fuel on both banks (e.g fuel pump, MAF, fuel injectors, ECT, fuel pressure regulator, things like that)

 

My fuel trims were off, I found the pvc hose all cracked and loose when I replaced the pvc valve. Instead of going back in with the Toyota formed hose I used 3/8” oil hose & worm gear hose clamps. Look closely, where the new hose wants to rub on a bracket I wrapped it with a zip tie to prevent wear. I’ve been meaning to recheck the trims but haven’t gotten around to it yet.