Runs rough and tapping, then it starts running normally?

2003 CHEVROLET SILVERADO
408,000 MILES • 6.0L • V8 • 4WD • AUTOMATIC
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MIKIE350
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  • 2 POSTS
Truck runs great at first then starts running rough and tapping like valves are dry. After a few minutes it clears up and runs normal.
Jan 13, 2023 at 9:03 AM
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JACOBANDNICKOLAS
  • Experienced Mechanic
  • 110,240 POSTS
Hi,

That is a new one for me. By chance is the check engine light staying on or flashing while the engine is running? Also, has the oil pressure light ever turned on while this happens?

Let me know. Also, if you had the computer scanned, let me know what codes were found. If not and the check engine light is staying on or flashing, have it done. Most parts stores will do it free of charge and let me know what you find.

Let me know what you find.

Joe
Jan 13, 2023 at 2:10 PM
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MIKIE350
  • MEMBER
  • 2 POSTS
Sorry yes, the engine light blinks and the code is mass air flow sensor. I have replaced that and reset the codes. But it still does the same thing. I don't have an oil light, just gauges.
The engine runs strong until this happens with no misses or unusual noises.
Jan 13, 2023 at 10:07 PM
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JACOBANDNICKOLAS
  • Experienced Mechanic
  • 110,240 POSTS
Hi,

If the check engine light is flashing, that indicates a cylinder misfire. What code did you get for the MAF? Also, are you sure there are no other codes stored?

Also, when you hear the noise and it starts running poorly, does the oil pressure gauge drop?

If it is possible, could you record what you are hearing? The idea that the check engine light flashes when this happens and it indicates a misfire, which would explain the poor running. If the oil pressure gauge doesn't drop off, we may be dealing with something totally different than an internal engine issue.

Let me know as much as you can.

Joe
Jan 14, 2023 at 12:28 PM
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