Hesitation on acceleration
Thread Starter
Pro
Joined: Jun 2007
Posts: 713
Likes: 9
From: Saratoga Springs Ut
Hesitation on acceleration
I picked up a 2000 M6 with 78k on it. I runs pretty good but it has a bit of a lag or flat spot off idle. When I take off from a light or stop sign and don't have the rpm up high enough it will bog and almost die I have to almost slide the clutch. I was thinking the mass air might be dirty along with maybe the TB? I do have HP tuners if there is something I can change with that.
Le Mans Master
Joined: Mar 2006
Posts: 5,775
Likes: 585
From: Texas
I'd stick with simple first. As you say, it might just be a dirty MAF. But check for cracked hoses going into the intake as well as missing or disconnected vacuum lines, and listen for exhaust leaks. Any of these can throw off the O2 sensor readings, causing misfires and hesitation.
Melting Slicks
Joined: Nov 2005
Posts: 2,297
Likes: 156
From: Clayton New Jersey
A few years back I had a 2000 Vette with the m6. I was having a very similar problem. I took it to the dealer, out of warranty, and once they hit $700 in diagnostic fees I told them to stop. I picked the car up and stuck it in the garage angry as hell. I had purchased a Vararam Intake and decided to just go ahead and install it. When I removed the factory air box I found a piece of foam, from the seal around the inside of the air box, inside the MAF sensor. When I accelerated the foam would partially block airflow. My issue was solved...very expensive lesson. Good luck
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I agree,,,,, Start with the simple stuff first. Clean the TB, MAF and check the piping between the MAF and TB for leaks. Also check the PCV piping and rubber hoses for damage. Very common for the Y fitting and tubing behind the manifold to crack and leak.
Safety Car
Joined: Dec 2010
Posts: 3,938
Likes: 498
From: Fords, NJ
Wouldn't hurt to check the Air filter either while your at it.
Racer
Joined: Aug 2016
Posts: 317
Likes: 42
I put a CAI on my 2003 a while back, mainly just to have something to tinker with in the winter and I couldn't believe how dirty the factory air cleaner was with 66,000 on the car which is otherwise imaculate.
I've honestly never saw a filter that dirty and how the car ran so good like that is beyond me and good mileage too. I don't think it was ever checked but everything else on the car was spotless.
I've honestly never saw a filter that dirty and how the car ran so good like that is beyond me and good mileage too. I don't think it was ever checked but everything else on the car was spotless.
Melting Slicks
Joined: Nov 2008
Posts: 3,146
Likes: 203
From: Edmonton Alberta, Canada
I had the same on my '03 a filthy air filter at 25k miles. I was floored when I seen how dirty. Difference was my MN6 Corvette idled real low (500 rpm) but after replacing filter and half hours driving it now idles at 800 rpm. (That was 2 years ago) These filters really suck up the dirt...not like your DD for sure. Now a suggestion for OP. Clean the throttle body and MAF, bring it in to be done if not comfortable doing it. I am betting a dirty throttle body is the issue also replace air filter as it probably needs it IMHO. Many times these simple fixes are overlooked...just for that reason. Good luck.
Last edited by El original; Mar 8, 2017 at 08:39 AM.
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Advanced
Joined: Feb 2016
Posts: 99
Likes: 18
From: Kirkland WA
I wasn't having the quite same hesitation problems, but I recently pulled my manifold a found a few issues which could be related.
I found the #2 and #5 bolt on my intake manifold was loose to the point I could actually unscrew it with my hands. I also found the rear vacuum line was broken, and the MAP sensor had the rubber o-ring crunched:
Ran new vacuum line from the manifold to the vacuum tank in the passenger side underneath the battery
and then also cleaned the MAP sensor and throttle body. The car certainly drives smoother and feels more responsive after my work, but it's also entirely possible this is all in my head.
Melting Slicks
Joined: Sep 2011
Posts: 2,258
Likes: 543
From: Appleton WI
All good advice. Cleaning the MAF and throttle body isn't difficult but beware that you need to use the spray cleaner specifically for MAF and NOT touch the delicate wires. Some people have the desire to wipe the wires but that can damage them.
As el Original stated, take it to a mechanic if you're not comfortable. At least you can give the mechanic specific direction on what you want done.
Lastly, let us know what you find. Including if you tried something and it didn't work. It gives us clues to continue working with you.
As el Original stated, take it to a mechanic if you're not comfortable. At least you can give the mechanic specific direction on what you want done.
Lastly, let us know what you find. Including if you tried something and it didn't work. It gives us clues to continue working with you.
Thread Starter
Pro
Joined: Jun 2007
Posts: 713
Likes: 9
From: Saratoga Springs Ut
I cleaned the MAF with a MAF cleaner and also cleaned the and lightly re oiled the air filter, it was pretty dirty but didn't seem to help much. This is my second M6 that I've owned so yeah I know how to drive it.
I need to go back over and check for cracked lines and so forth. I am going to replace the plugs and wires as well just because the wires look original. When I picked the car up and was driving it home I did notice a missfire as well under load once or twice but never again. The car was owned by an older woman and I imagin that she drove it fairly mildly so there could be some carbon build up. Like my dad use to say, you need to blow it out.
I need to go back over and check for cracked lines and so forth. I am going to replace the plugs and wires as well just because the wires look original. When I picked the car up and was driving it home I did notice a missfire as well under load once or twice but never again. The car was owned by an older woman and I imagin that she drove it fairly mildly so there could be some carbon build up. Like my dad use to say, you need to blow it out.
Advanced
Joined: Feb 2017
Posts: 77
Likes: 5
Yup, just purchased my car with the "Certified 125 point inspection" from the dealer.....right... Car has 39,000 miles. if you just purchased your vette start out with installing new oil, filters, fluids. Don`t trust it unless you changed yourself or paid for it yourself.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08