Tundra starts and dies/backfires NEED ADVICE!

2004 4.7L Tundra, well maintained 150K miles. Having issues, died on the highway going downhill, haven’t been able to run the engine without it dying. Here’s a video I took while my girlfriend started it up. Any ideas? I’m thinking fuel system issue or ignition? Doesn't have a problem cranking, usually once it starts up it’ll run for a little then die.

 

https://drive.google.com/file/d/1hAXqixO_0hy-lMwxkqQSFlSaU73w4j2I/view?usp=drivesdk

This is the video. Full tank of gas as well.

 

Could be caused by any number of things.

But as a rule, backfire is caused by a LEAN condition. ie, not enough fuel.

So...bad sensors, bad fuel injector, bad fuel pump, bad fuel pressure regulator...

 

Clean the MAF first. Cheap and easy. Or even easier and free, unplug MAF and see if it runs at all.

 

Gonna see if I can try this

 

Not too sure what to expect it’s about 20 years old. Thought it was invincible lol

 

Didn’t work, no change

 

Have you very carefully inspected the myriad of air lines for cracks/leaks?

 

I did a general inspection but didn’t notice any major issues. We’ve never had an issue with this truck so it was sudden

 

Have you scanned for codes? That would be the #1 thing I would do. It’s potentially free clues that may directly answer the problem.

I’m guessing fuel pump or other fuel delivery issue but … there’s nothing yet I see narrowing down the possibilities…

 

Hello? As Shifty said, every good mechanic does this first, even if there is no CEL light on, there may be a Pending code, about to be set, the answers are there. Tell us what you find.

 

Yes I would scan if I could, not only is the check engine light bulb not working but I don’t have a scan tool, also can’t get the truck to a place that would have one. Trying to see if a friends mechanic can pass by for a plug and play diagnosis.

 

If nothing else, I see scAmazon has at least three diagnostic code readers for under $50 which are available for same-day delivery to me at the moment. Don’t need anything special. Just something OBDII compatible. It’s something every person should have on-hand, and if it saves you from buying a single “guess” part once, it just paid for itself.

 

Does it stay on if you give it gas? Also try cleaning your throttle body. Make sure your battery connections look good and are making proper contact. Easy stuff first.

 

It’ll die regardless even giving it gas

 

We’re gonna read the computer tomorrow, in the case that it’s a fuel pump where can I get an OEM one?

 

I mean, you can order one discounted at https://parts.toyota.com if you plug in your VIN, then pick it up at your nearest participating Toyota dealership (which is nearly all I've seen).

But if you have a Summit Racing near you, or you wanna order from RockAuto, anything Denso or Aisin is OEM-equivalent, if not straight-up OEM.

 

Local parts counter or @Roman from Toyota of Cool Springs.

 

What’s the history on your timing belt? A cog or three out of time can do this, though you will have code(s) to go along with it.

 

The video is by permission only. I just requested permission, but you may want to unlock it for others to view.

 

Getting the codes read out today, I’ll let you know what we get

 

Just gave permission thank you

 

So a really good mechanic went through it, CPS(crankshaft position) is damaged non functioning, RPM is not being read by snap-on computer, battery is screwed as well

 

That's better than snapped timing belt.

 

Strange, when I did my timing belt and didn't get the CPS connection fully seated it through a code for CPS when I started it. Glad you've got something to go with and hope it fixes the problem!

 

That’s a pretty easy fix. The Crank shaft sensor is located on front of the engine right behind the crank pulley, remove your skid plate and fan shroud for easier access, btw I recommend getting OEM part.

 

Isn't the crankshaft position sensor the one whose wire often gets rubbed through if not properly restrained during a timing belt change? Or am I thinking of the knock sensor? I've had a looong f'n day.

 

Crank sensor was changed and fixed our issues, oil leaks are up next to be patched up! Thanks for the help guys!