Rough idle
Thread Starter
Melting Slicks
Joined: Sep 2004
Posts: 3,024
Likes: 18
From: DFW Texas
Rough idle
Noticed while sitting at stop lights (some very long), in neutral (MN6), the engine feels like it is missing every now and then. Almost sounds like it has high perf cam, but definately just rough idle. Around 800 RPM
Once the RPM's come up, isn't noticeable, but suppose it still could have a mis-fire - just don't feel it in higher RPM's.
There are no codes in the DIC, current or past... starts right up every time.
Stat's: 99 coupe. MN6, 50k miles, almost 100% stock except for B&B PRT's. Bought a couple of months ago. Everything works on it - ZERO issues, other than the rough idle.
Ideas? Thoughts?
Once the RPM's come up, isn't noticeable, but suppose it still could have a mis-fire - just don't feel it in higher RPM's.
There are no codes in the DIC, current or past... starts right up every time.
Stat's: 99 coupe. MN6, 50k miles, almost 100% stock except for B&B PRT's. Bought a couple of months ago. Everything works on it - ZERO issues, other than the rough idle.
Ideas? Thoughts?
Race Director
Joined: Oct 2004
Posts: 18,401
Likes: 3
From: Retired but working
Cruise-In VI Veteran
I've got a 99" LPE coupe it's in neutral or park the idle is a bit rough, but its the cam. Other than that I don't notice it a bit.
On my 63' SW the cam was quite huge so I noticed it all the time with the clutch in. That's until you squozze down on it.
On my 63' SW the cam was quite huge so I noticed it all the time with the clutch in. That's until you squozze down on it.
Race Director
Joined: Jun 2000
Posts: 13,733
Likes: 66
From: Hurst, TX USA
Originally Posted by diyguy
Noticed while sitting at stop lights (some very long), in neutral (MN6), the engine feels like it is missing every now and then. Almost sounds like it has high perf cam, but definately just rough idle. Around 800 RPM
Racer
Joined: Jun 2004
Posts: 474
Likes: 0
From: Moncks Corner South Carolina
My 99 shakes when sitting in neutral. You can't see it from outside, but you can feel it sitting inside the car. I figure it's a sportscar, so I guess it should shake and rattle a little.
Supporting Vendor
Joined: Mar 2002
Posts: 2,073
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From: Loveland CO
If it just feels like it misses a little it is common. I can even feel it in my moms 01 and it is an automatic. I think it is fairly common in a lot of GM vehicles (don't know about other companies). I have a 00 Silverado automatic and it does it at stop lights as well. Kaley
Premium Supporting Vendor
Joined: Oct 2004
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From: Manassas Park VA
St. Jude Donor '07-'08,-'13-'14, '16-'17
Mine is new but I changed the plugs and wires and it smoothed out quite a bit. Also check the MAF and gently clean the wire.
Good Luck
Peace
Willfulone
Good Luck
Peace
Willfulone
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Last edited by CCA Corvette Parts; Dec 16, 2004 at 06:06 PM.
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From: West Palm Beach FL
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St. Jude Donor '05-'06-'07
Originally Posted by stangkiller18
I'd check the air intake make sure it's nicely sealed. Maybe change the plugs. Good luck on finding the rought idle!
...this coming from a guy who has a rough idle and wont do anything about it
...what he said...
...and check that plug wire connected securely...
Team Owner
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bad wire....it should shake a bit but if it is more noticeable than usual...check the wires....probably one going bad
Melting Slicks
Joined: Nov 2003
Posts: 2,898
Likes: 5
From: Plainfield, IL
my 99 FRC with 20K miles does the same thing. Car runs very strong no issues except kinda choppy idle it seems. One of these days I will throw in some decent wires and plugs. See if that helps any. Im not to worried about it though.
Drifting
Joined: Mar 1999
Posts: 1,514
Likes: 38
From: Woodland Wa
These engines need to re-learn the idle now and then, I dont recall the exact method but you basicly allow the enigne to idle about 10 min. the shut off the engine and start it back up, and the computer will do the rest.
