is this normal at idle?
Thread Starter
Instructor
Joined: Mar 2008
Posts: 247
Likes: 1
From: Westchester NY
is this normal at idle?
I bought my 2000 c5 6speed about 5 weeks ago and I love it. I'm still getting used to some things though and I was wondering if they are normal. The car has a slight vibration when sitting at idle. You can feel the engine shaking the car slightly. You can feel it and really see it after i mounted my cellphone holder. You can barely read what the phone says because of the vibrations. I came from a new civic which you could barely tell if it was on so I'm not sure whats normal for a c5. Oh and it has 36k miles on it. Thanks
Melting Slicks
Joined: Feb 2006
Posts: 2,172
Likes: 104
From: Des Moines Iowa
maybe, just maybe you have some bad spark plugs. I understand that the OEM plugs sometimes have a tendency to lose the insulator, at least I've read that it''s not all that unusual. Perhaps a new set of plugs and red GM high performance wires, would be a good idea.
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
When you describe a "slight" vibration .... that's pretty subjective .... 
Certainly for an OHV 8 cylinder engine generating 1 HP per cubic inch (and more) you should not expect as smooth an idle as a Cadillac or Lexus will give you. On the other hand, Chevy has done an amazing job of smoothing the idle so that it is reasonably smooth.
Couple of things to consider .....
1) Watch your "CHECK ENGINE" light at idle .... if it is flickering on and off then something is not right with your engine.
2) See if the engine computer is sensing a mis-fire condition. Dump the DTC data and see if a P0300 code is posted. If you are unsure how to display the data .... go here ....
https://www.corvetteforum.com/techti...D=26&TopicID=1
Post any/all codes that you find and someone can help you interpret them.
With 36k miles on it, the plugs and wires should be fine ..... but if you want to .... I'd do the following to ensure a smooth idle and good engine performance .....
Install new spark plugs (AC Delco 41-985) which come correctly pre-gapped at 0.040 inches.
Install new spark plug wires - get the GM Performance Parts (GMPP) kit part number 12495519 (available from any GM parts seller - and the kit includes all 8 wires) .... be sure the wires click twice on installing the coil end ... click once installing the spark plug end.
Main thing is .... dump the DTC data .... if there is a "problem" the PCM has probably recognized it .... let's see what it says.
Certainly for an OHV 8 cylinder engine generating 1 HP per cubic inch (and more) you should not expect as smooth an idle as a Cadillac or Lexus will give you. On the other hand, Chevy has done an amazing job of smoothing the idle so that it is reasonably smooth.
Couple of things to consider .....
1) Watch your "CHECK ENGINE" light at idle .... if it is flickering on and off then something is not right with your engine.
2) See if the engine computer is sensing a mis-fire condition. Dump the DTC data and see if a P0300 code is posted. If you are unsure how to display the data .... go here ....
https://www.corvetteforum.com/techti...D=26&TopicID=1
Post any/all codes that you find and someone can help you interpret them.
With 36k miles on it, the plugs and wires should be fine ..... but if you want to .... I'd do the following to ensure a smooth idle and good engine performance .....
Install new spark plugs (AC Delco 41-985) which come correctly pre-gapped at 0.040 inches.
Install new spark plug wires - get the GM Performance Parts (GMPP) kit part number 12495519 (available from any GM parts seller - and the kit includes all 8 wires) .... be sure the wires click twice on installing the coil end ... click once installing the spark plug end.
Main thing is .... dump the DTC data .... if there is a "problem" the PCM has probably recognized it .... let's see what it says.
