2000 GMC Sierra Revs to Redline When Started (Videos of the Issue)

[Odin]

Hello,

I was driving my 2000 GMC Sierra 5.3L when it died on me in the middle of the road. I tried to start it, but the engine cranks but didn't run. After I left it for 30 minutes, I started it again and when it started the engine revs all the way to redline without me touching the gas paddle. It keeps doing that every time I start the car, and there is no way to stop it.

 

This is the things I have done since the problem started:

I checked and cleaned the throttle body, and it is not stuck wide open. 

I checked and cleaned the IAC valve. 

I checked the Accelerator Cable, and it looks fine.

I looked for vacuum leaks, and I couldn't find any.

 

Here is a video of the issue:

https://youtu.be/d7ILg5Tv9dg

 

Another video( here when the revs reached 3500 it dropped to 2000 then the car died and never didn't again(until I left it for 30minutes) ):

https://youtu.be/gR-O2QJaDQY

[sefiroxx]

Useful of someone is watching the throttle when starting. In general though - vacuum leak. Brake, pcv, egr etc

[Odin]

2 hours ago, sefiroxx said:

Useful of someone is watching the throttle when starting. In general though - vacuum leak. Brake, pcv, egr etc

I had someone watching the throttle when i started it and he saw nothing happening to throttle. I can't diagnose vacuum leaks properly since I can't get the car to run. I will check the brake and pcv. BTW, the car have an EGR delete kit

[sefiroxx]

For grins, plug the throttle air intake and see if it is better

 

Any codes?

Fuel pressure confirmed?

Do scanner readings for sensors with car on look reasonable?

 

[Odin]

4 hours ago, sefiroxx said:

For grins, plug the throttle air intake and see if it is better

 

Any codes?

Fuel pressure confirmed?

Do scanner readings for sensors with car on look reasonable?

 

1

What do you mean by plugging the throttle air intake? because the air intake is already plugged. 

I will get the codes today and update you.

[sefiroxx]

Throttle has a minimum air bypass and may be held open a bit by the iac. Plugging would shut off all air through this passage , and if the engine runs, indicate a vacuum leak somewhere else.

[Odin]

New update,

I've disconnected the MAF sensor to kind of stop the computer from sending to much fuel to the engine. The rev didn't jump to redline like always, but it kept going slowly until it reached 2.5k and I stopped the engine. Two things happened in the engine, first one there was sparks coming from the throttle body (I will attach a picture of the area). Second smoke came out from the passenger side headers. Also, there is a strong smell of fuel coming.

 

Here is a video of the car running without a MAF sensor:

Edited February 24, 2019 by Odin

[Odin]

Here are the codes.

[Odin]

FINALLY after two months, i found the issue. There was BIG hole in my intake manifold causing the air to go right through. I changed the intake manifold with a new set of injectors and the car now runs perfectly. I hope this post helps anyone having the same issue i had. Here is a video and some pictures of the intake manifold. 

https://youtu.be/DSyNdiGt2d0

[Gagliano7]

Seemed like a vacuum leak but that is pretty crazy where it broke.