1997 Toyota Corolla Engine Knock

Tiny
DR1TTZ
  • MEMBER
  • 1997 TOYOTA COROLLA
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 115,000 MILES
I changed the spark plugs in the car just as I have done before. I start the car and the engine knocks.
I think that maybe something was wrong with the new plugs so I put the old ones back in. The knock stays.
It is an overhead problem as it increases with RPM.

I checked the oil and its not low, although it could probably use a change (its my grandmas). The knock goes away when the car warmed up. I parked it to listen some more. I revved the car to 4k and it was fine.

I let the RPM's drop and it was ok for a few seconds. Then the car kind of choked and the rpms seemed to fluctuate low. The knock began again. I gassed it a little and the knock stayed.
Saturday, March 20th, 2010 AT 6:16 PM

3 Replies

Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
If all you did was change plugs, then you may have got the wires mixed up.
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Sunday, March 21st, 2010 AT 7:28 AM
Tiny
DR1TTZ
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I did them one at a time to make sure they stayed in sequence
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Sunday, March 21st, 2010 AT 11:11 AM
Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
A knock would indicate a rod or main bearing. I don't know how changing plugs could cause this.
The wrong plug could actually hit the piston causing mechanical damage, but taking out the old plug, it would be evident that the plug was damaged, if so then debris may be in the combustion chamber.
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Monday, March 22nd, 2010 AT 7:38 AM

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