car rough idling.. maybe
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Joined: Feb 2023
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car rough idling.. maybe
My car sounds like its been idling kind of rough. When i put it in drive it sounds like it wants to die. A mechanic pointed out that i might want to change the fuel filter but i cant find a fuel filter on this car so i guess he meant regulator. before all this i tried getting a custom tune from diablo but dude wouldn't tune it because it was 'running way to lean' but there is no reason that i can see for it running lean, i havent had the car for long you guys would know better than me. Below is the video of my idling and me putting it in drive the car looks a little rough inside because im still fixing it up the guy before didn't treat it right. Its running on a diablo 93 octane tune so its richened a bit.
Don't know if it matters or not but here is the specs of the car
2004 corvette
A4 transmission
borla catback s-type single
texas speed headers and x-pipe
vararam system just with K&N filter on
diablo 93 octane tune
Don't know if it matters or not but here is the specs of the car
2004 corvette
A4 transmission
borla catback s-type single
texas speed headers and x-pipe
vararam system just with K&N filter on
diablo 93 octane tune
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Joined: Sep 2013
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From: Cape Coral, Florida
There are many causes for the car to run rough so there will be no magic bullet here…does the car run better under load ??…if it runs better this can be a vacuum leak…you can try disconnecting the MAF sensor and see if it runs better…without a scan tool to look at “live data” you’ll only be guessing.
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it runs good under load at least i think so, ive noticed without my foot on the throttle it sounds a little weird like its dipping in and out rpm's but my tachometer isn't working at the moment. when i put even the slightest bit of throttle on the car it sounds like it starts running normally. when i got the car it sounded like something was done cam wise which went away with the tune. I'm sure if i took the tune off it would start up again
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Start with looking for obvious medium to large vacuum leaks. One of the most common vacuum leaks is the PCV vacuum hose. . Look on the passengers side of the engine. intake manifold There will be a vacuum fitting on the front neck of the intake manifold just to the rear of the throttle body. There's a short "U" shaped formed rubber vacuum line that goes directly into the engine valve valley cover. PCV system. The rubber hose is well known to rot, split and leak. Examine the Air Bridge /MAF assembly between the MAF and the Throttle Body. Look for ANY air leaks that may allow un-metered air to enter the engine.
If a visual inspection doesn't expose any hard results, you can spray some Brake Parts Cleaner on any vacuum exposed area on the air bridge, TB, Intake Manifold to head area and see if you get any effect on running engine idle quality.
If a visual inspection doesn't expose any hard results, you can spray some Brake Parts Cleaner on any vacuum exposed area on the air bridge, TB, Intake Manifold to head area and see if you get any effect on running engine idle quality.
Drifting
Joined: Nov 2019
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From: SC
Don't know if it's your issue or not but the fuel filter is up on the drivers side of at the rear of the car near the exhaust and transmission
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Late 2003 and ALL 2004 C5 Do NOT have a frame mounted external fuel filter. They use a 2005 style fuel tank with a filter sock inside the tank. In fact, you can NOT access the pumps, filter or any electrical or fuel pluming connections without dropping down the tank assembly. The fuel tanks and fuel system is completely different than any earlier C5s.
