Misfire on cylinder 3?

150,000 MILES • 6.2L • V8 • 4WD • AUTOMATIC
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JESSICA SATERMO
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  • 1 POST
I have a misfire on cylinder 3 and a random misfire. I changed the spark plugs, the wires, the coil packs, the injectors, the MAF sensor, and nothing worked. I changed the MAP sensor and that fixed the problem for about 2 days. I also sprayed either checking for a vacuum leak and the engine didn't pick up, so I concluded I did not have a vacuum leak it only seems to miss at low speeds like driving through town but on the highway, it seems to run fine. My check engine light stays on for the most part sometimes flashing but when the traction control light comes on my oil pressure goes up.
Oct 12, 2023 at 9:01 AM
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STRAILER
  • ✓Experienced Mechanic
  • 55,588 POSTS
It sounds like you may have low compression on that cylinder, to be sure this guide will show you how to get the compression reading which you can rent the gauge set at the auto parts store for free or cheap:

https://www.2carpros.com/articles/how-to-test-engine-compression

Please go over this guide and get back to us.
Oct 12, 2023 at 9:49 AM
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