Contour Enthusiasts Group Archives Forums General Troubleshooting Engine Comp't. Rattle Under Hard Acceleration

I have a '99 SVT with 45K miles, running well.

This summer under hard acceleration with windows down I can hear a rattling sound from up front. The rattle reminds me of pre-ignition, except it seems to be coming from below. The heat shield on the cat is not loose, and I can't duplicate the sound by shaking or banging on the exhaust system. No other loose parts underneath the car. The sound happens whether or not the A/C is on. My butt-dyno detects no deterioration in engine performance and the clutch isn't slipping. I use 92 octane fuel. My guesses:

- Pieces of pre-cat rattling in the exhaust
- a clutch-related sound (I know what the low-speed clutch rattle sounds like).
- Some part of the SVT front valance, though I've recontented the two lower braces from the 98's.
- Pre-ignition and I just am not used to the sound in a newer car.

Search under keywords rattle, high, rpms, WOT, acceleration, came up with zip.

Any ideas?

Thanks in advance!

a search using 'pinging' will get you 2 hits, many opinions, but no firm conclusions.