Truck shakes when driving over 30 mph

1999 CHEVROLET SUBURBAN
200,000 MILES • AUTOMATIC
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JOANNAG32
  • MEMBER
  • 1 POST
My engine light turn on went to get it checked as i go over 30 the inside of my truck shakes a lot, it smells like gas when i have window down even when i slowly move it forward it shakes. I don't go over 50 because i'm afraid something will happen. I took it Pep Boys. I got a tune up and PCV changed.. I knows it's misfiring others suggested it's a oxygen pump clogged.. I was just going to sell it but if y'all have other options to what it could be it be very helpful.
Feb 3, 2020 at 5:28 PM
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KASEKENNY
  • ✓Experienced Mechanic
  • 18,907 POSTS
Did they pull the codes while you were there? It would be helpful to know if you have multiple cylinders misfiring or even an sensor issue that could cause this issue.

The fact that you smell fuel is an indication that it is running rich but that may just be a symptom of an mass air flow sensor. If the amount of air coming in is not accurate then the PCM will not add the correct amount of fuel.

Let's start with the codes and go from there. Thanks.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge
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Feb 4, 2020 at 7:10 AM
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