Diagnosis
Thread Starter
Intermediate
Joined: Nov 2024
Posts: 40
Likes: 0
From: Miami
Diagnosis
My friend wrote the following about his C7 Manual Stingray 2016 Corvette:
Starting off the drive from neutral to first gear. I ease off the clutch until the biting point and at this point I usually blip the throttle to give it a bit of gas and start rolling. Usually the tiniest blip would rev the car loud as it should but lately the car would sound low/muffled or won’t sound off at all. The rpm’s would still go up tho. So now with this issue, I’m forced to add more pressure to the throttle than before to just get the car rolling. There had even been times where I’m blipping the throttle bit by bit, rpm’s go up and the car doesn’t want to move and if finally started moving after my foot was basically halfway down the accelerator. Down shifting is another issue but is still connected with this throttle issue. Anytime I blip the throttle to downshift it sounds like it cuts itself off which then leads me to lug the car. Usually when I blip it, it would do a AHHHHHH loud reving sound like normal but now it would go AHH—- and cuts off. The car doing that forces me to strictly drive with rev match on cuz I don’t wanna ruin the clutch trying to drive it normally with that issue still occurring. But even with rev match on it still does that half *** rev sound when downshifting. The car has an aftermarket intake, long tube headers, tsp xpipe, and a corsa exhaust. It shouldn’t be sounding so low like it is now. It sounds almost stock when idling. Recently got it tuned to see if that would fix the problem but nothing changed minus all the codes being wiped. Previous owner installed all those aftermarket parts and has had the car with the check engine light on the whole time. I got it from the dealership that way and left it as is cuz it was driving fine without the need of the tune. This issue started happening a couple weeks back and I’ve owned the car since October 2024. Tuning it didn’t help and my tuner/mechanic doesn’t find any issue other than the car running lean. Idk how it’s running lean but any info would help
Starting off the drive from neutral to first gear. I ease off the clutch until the biting point and at this point I usually blip the throttle to give it a bit of gas and start rolling. Usually the tiniest blip would rev the car loud as it should but lately the car would sound low/muffled or won’t sound off at all. The rpm’s would still go up tho. So now with this issue, I’m forced to add more pressure to the throttle than before to just get the car rolling. There had even been times where I’m blipping the throttle bit by bit, rpm’s go up and the car doesn’t want to move and if finally started moving after my foot was basically halfway down the accelerator. Down shifting is another issue but is still connected with this throttle issue. Anytime I blip the throttle to downshift it sounds like it cuts itself off which then leads me to lug the car. Usually when I blip it, it would do a AHHHHHH loud reving sound like normal but now it would go AHH—- and cuts off. The car doing that forces me to strictly drive with rev match on cuz I don’t wanna ruin the clutch trying to drive it normally with that issue still occurring. But even with rev match on it still does that half *** rev sound when downshifting. The car has an aftermarket intake, long tube headers, tsp xpipe, and a corsa exhaust. It shouldn’t be sounding so low like it is now. It sounds almost stock when idling. Recently got it tuned to see if that would fix the problem but nothing changed minus all the codes being wiped. Previous owner installed all those aftermarket parts and has had the car with the check engine light on the whole time. I got it from the dealership that way and left it as is cuz it was driving fine without the need of the tune. This issue started happening a couple weeks back and I’ve owned the car since October 2024. Tuning it didn’t help and my tuner/mechanic doesn’t find any issue other than the car running lean. Idk how it’s running lean but any info would help
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,615
Likes: 4,062
From: Cape Coral, Florida
Find a diagnostic shop in your area and take the car there…there is not anything we can do for you as far as a diagnosis…try Autobahn Performance in Oakland Park…talk to Mario Rojas.
Safety Car
Joined: Sep 2005
Posts: 4,226
Likes: 643
From: Orange County Ca
I have found, surprisingly, that a free code scan from AutoZone (maybe other parts stores also) was very complete. Also included with the code scan, was a list of probable causes which can many times lead you to do further research. Of course, a good diagnostic shop would be the quickest/easiest, but all so mucho $$$. Rates here in commiefornia are around $200/hr.
And, how can you beat free?
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Racer
Joined: Sep 1999
Posts: 422
Likes: 20
From: Upstate SC
Cruise-In I Veteran
Reading your description I would guess clogged cats, especially considering the change in the exhaust sound. If that was the problem the tuner should have identified it easily though...
Safety Car
Joined: Sep 2005
Posts: 4,226
Likes: 643
From: Orange County Ca
There are a few Corvette specialty shop around the Los Angeles area. These https://americanheritageperformance.com/ charge dealer prices or more, but there reputation is 5*****. Very knowledgeable and very professional work. Worth it in my opinion.
