I have a 99'chevy camaro z28. It has been accelerating very slowly and eventually dying on me. I've changed the battery, spark plugs and the fuel filter. It manages to turn on and stay on fine. It has 310 Hp, but when I floor it, it feels as if it only had 100 Hp. This started happening after loose rocks on the road hit the under side of my car. I checked for damage but see nothing? What could be going on?

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    Have you tried to see if it runs well at almost wide open throttle. In other words, not getting on it so hard, then see if speed increases a little better? The 98 still had a drive by cable system. I'm thinking this may be a throttle position sensor issue, or it could possibly be a low fuel pressure issue. The fuel pressure could be checked at the fuel rail, though I don't remember what pressure the LS1 engine was supposed to have off the top of my head (60psi I'm thinking?). Commented Jul 14, 2016 at 23:40
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    @Pᴀᴜʟsᴛᴇʀ2 and a fuel line could have gotten damaged from rocks in theory. Since the TPS is usually top-side I wouldn't think it would... Commented Jul 15, 2016 at 0:00
  • @kyle_engineer - I'm looking more at symptoms than worrying about whether a rock hit something. If the TPS was not registering at WOT (or registering wrong), it would be a dog. Same if fuel was not giving proper pressure at WOT. The rock hits may just be coincidental. Commented Jul 15, 2016 at 0:06
  • @Pᴀᴜʟsᴛᴇʀ2 True Commented Jul 15, 2016 at 0:39
  • Is the check engine light on?
    – tlhIngan
    Commented Jul 15, 2016 at 2:52

1 Answer 1


If you suspect the loose rocks may have caused this:

  • check the air intake for cracks and leaks (leaning out the mixture too much)
  • look at the steel fuel lines for kinks (poor fuel delivery)
  • inspect the exhaust for kinks (too much back pressure)

If you don't think the rocks did this, you should do a compression test and take it from there.

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