Engine noise ran fine but had a rough idle?

Tiny
CURTIS B
  • MEMBER
  • 2004 CHEVROLET CORVETTE
  • 5.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 50,000 MILES
I got the 2004 C5 at 37k miles and it had aftermarket cam, headers, exhaust, and cold air intake already at purchase. It ran fine but had a rough idle. I took it to a very well respected Tommy Chong to have it tuned. Ran great on non-ethenyl gas but was constantly needing maintenance. Too many to list I had just replaced belt tensioner and idler pulleys and went on a drive and got what sounded like belt of pulley noise again and thought it A/C belt or pulleys, but it wasn't. Took all belts off still the noise. A friend thought it was rocker noise, so I replaced it with up graded rockers still the noise. I took the hearing device with the rod and can't pinpoint the noise it seems to be traveling all through the engine. It sounds just like a bad pulley when standing next to it. I changed and looked at the oil and filter and it was clean, and performance wasn't affected at all. But it's loud and obnoxious. At this point I can't afford to take it to a shop. I would appreciate any thoughts on this.
Wednesday, July 2nd, 2025 AT 7:09 PM

2 Replies

Tiny
CURTIS B
  • MEMBER
  • 2 POSTS
As it turned out the rockers were in poor condition, there was considerable not just side to side but up and down rocking in them. But not the noise.
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Wednesday, July 2nd, 2025 AT 9:51 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,273 POSTS
I would remove the drive belt and start the engine to make sure it has nothing to do with the pulley system. If the noise is still there it will be inside the engine. Can you please shoot a quick video with your phone so I can hear the noise? That way I can tell for sure what's going on.
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Friday, July 4th, 2025 AT 9:27 AM

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