Codes 0300 and P1133

Tiny
SCHADIE03
  • MEMBER
  • 2001 CHEVROLET TAHOE
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 240,000 MILES
Truck revs to 3-3.5k RPMs after 20-30 MPH. So my truck has a p0300 and p1133 and had a lean code the other day so I went and bought a o2 sensor thinking it would fix it all and I put it in at the store and I was driving down the road a ways and my RPMs shot up to 3,000 I should probably mention I didn’t have the muffler bolted on at that time so either way I could really use some help figuring this out.
Saturday, March 19th, 2022 AT 8:28 PM

1 Reply

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
These could be a couple of things, but I would think that we have a vacuum leak more than any other issue.

So, let's start with using this guide to see if we can track one down. If so, we need to repair this and then retest.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Basically, these codes are pointing towards an air leak that is allowing unmetered air in or possible low fuel pressure so here are a couple things that will help with this:

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Assuming we don't find a vacuum leak or other issues listed, we need to move onto this testing and find out if we have an exhaust leak prior to the o2 sensors. I attached the testing for this so run through this and let us know what you find.

Thanks
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Sunday, March 20th, 2022 AT 6:58 PM

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