Annoying hesitation while accelerating
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Annoying hesitation while accelerating This is hard to explain and doesn't do it all the time. Every now and then while I'm accelerating normal, the car seems to hesitate and act like it doesn't want to go, then immediately starts driving fine...At WOT it doesn't do this, although i really haven't gotten on it much...It's basically just a hesitation like it doesn't want to accelerate easy...
Also, i started noticing it more when i dumped my exhaust. Car has stock manifolds and after the Y-pipe it dumps down...Maybe it's lean?
What do you think? This just occurred to me. Maybe fuel pump? What else could it be? I doubt spark plugs, because i would think the car would misfire at WOT...
Also, i started noticing it more when i dumped my exhaust. Car has stock manifolds and after the Y-pipe it dumps down...Maybe it's lean?
What do you think? This just occurred to me. Maybe fuel pump? What else could it be? I doubt spark plugs, because i would think the car would misfire at WOT...
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It's an A4, but the transmission shifts well. Solid shifts and no slipping. I had a tranny go out on my old Z28 and i can tell it starts feeling sluggish and slow. Shifts are weird and tend to slide into gear. This car doesn't appear to do that...
I would hope it isn't the tranny...lol, that would suck.
I should also add it doesn't do it from a stop, only while accelerating and it's very quick like it's losing power and coming back.
I would hope it isn't the tranny...lol, that would suck.
I should also add it doesn't do it from a stop, only while accelerating and it's very quick like it's losing power and coming back.
Teching In
Joined: Dec 2008
Posts: 34
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From: Austin, TX
I have the exact same problem as you describe and have a M6. It's consistently around 2-2500 RPM range. Type of fuel seems to make a little difference. At WOT it runs fine. I've read some other posts on the matter as well that lead me to believe it could be the primary 02 sensor. I've not tried to replace them as I hate spending the $ only to find it's not the fix. I'll try the gasket.
I took my TA to the track last week and could not get a good time in for the life of me and I'm hoping this is the cause. The best I could do was 15.5 @ 94mph. The car pulls but feels slow out of the hole.
I took my TA to the track last week and could not get a good time in for the life of me and I'm hoping this is the cause. The best I could do was 15.5 @ 94mph. The car pulls but feels slow out of the hole.
Mine has been doing the same thing. When I stop and and then take the foot off the brake the car doesnt move like it normally does. I have to give it gas and then the convertor kicks in then it drivs normally. Its done this twice now in the last 10 or so time Ive driven it.
Ive also noticed when its doing this that my idle is right under 500rpms.
I drive an A4
Ive also noticed when its doing this that my idle is right under 500rpms.
I drive an A4
Teching In
Joined: Dec 2008
Posts: 34
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From: Austin, TX
ccxxxxxxx, I don't think it's the same thing as we're experiencing. It sounds like you could have a problem with the IAC motor.
Camaro Owner, check out this thread. https://ls1tech.com/forums/general-m...s-wtf-wtf.html
Camaro Owner, check out this thread. https://ls1tech.com/forums/general-m...s-wtf-wtf.html
Last edited by brian.moritz; Aug 21, 2009 at 07:40 AM.
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Thread Starter
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ccxxxxxxx, I don't think it's the same thing as we're experiencing. It sounds like you could have a problem with the IAC motor.
Camaro Owner, check out this thread. https://ls1tech.com/forums/general-m...s-wtf-wtf.html
Camaro Owner, check out this thread. https://ls1tech.com/forums/general-m...s-wtf-wtf.html
I started noticing it A LOT more after i dumped my exhaust from the I-pipe...It isn't terrible, but annoying. It does feel like it's choking fuel, or something...I do have a K&N and maybe that's dirty? I'm thinking i need a tune up, but i don't think it's the spark plugs, because the car seems pretty quick at WOT. Cleaning the MAF seems to be a good idea and while I'm at i suppose i should descreen it? I've heard that descreening the MAF makes your car more responses and this is something that could potentially help. So, maybe the MAF is really dirty and the screen is causing it to choke a little?
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Joined: Dec 2008
Posts: 34
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From: Austin, TX
Cleaning MAF fixed my hesitation I cleaned the MAF and wow what a difference! Can't wait to get back to the track and see what time I can get down now. It made a significant difference for me but then I've had the K&N in for close to 25k miles now. Also had the clear lid on and I put stock back on. That clear lid is a POS.
I had the exact same problem from 2300-2700 RPM. At full throttle the car ran like a bat out'a Hell. Here's the list of things I went through to solve the problem. . .
Replaced Throttle Position Sensor . . . no help
Replaced both of my O2's to New Bosch 13111 . . . no help
Replaced plugs and wires with ACDelco plugs and MSD 8.5's . . . no help
Took the Throttle body off and cleaned it and did a fuel injection service. . . no help
Cleaned my IAC Valve . . . no help
Cleaned my MAF . . . no help
Replaced Fuel pump with Walboro 255 . . .found the old one was going out anyways but no help again
Finally got a simple street tune and the car drives 10,000 times better. It's by far the best the car has ever run.
Please keep in mind how much of a difference a tune will make on these cars. Even with a small amount of bolt-ons. Even enough time with a stock vehicle and I'm sure you could see a small amount of difference.
Hope this helps.
Replaced Throttle Position Sensor . . . no help
Replaced both of my O2's to New Bosch 13111 . . . no help
Replaced plugs and wires with ACDelco plugs and MSD 8.5's . . . no help
Took the Throttle body off and cleaned it and did a fuel injection service. . . no help
Cleaned my IAC Valve . . . no help
Cleaned my MAF . . . no help
Replaced Fuel pump with Walboro 255 . . .found the old one was going out anyways but no help again
Finally got a simple street tune and the car drives 10,000 times better. It's by far the best the car has ever run.
Please keep in mind how much of a difference a tune will make on these cars. Even with a small amount of bolt-ons. Even enough time with a stock vehicle and I'm sure you could see a small amount of difference.
Hope this helps.
Staging Lane
Joined: Apr 2006
Posts: 68
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From: Troy, MI
I noticed a similar thing a couple of years ago, shortly after it started I hooked up hp tuners and saw that my maf was reading incorrectly and that there was knock retard ocurring when I noticed the hesitation. I unhooked the maf to run in sd mode and it went away.
Teching In
Joined: Dec 2008
Posts: 34
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From: Austin, TX
Cleaning MAF fixed my hesitation I don't know maybe there are different brands out there? But my main disappointment is the fit, not the performance. When you put it on the tabs in the back feel like they are awfully close to snapping off. It ends up bending the lid around the edge of the filter and does not look like a good seal. From the lid to the MAF the seal there is fairly poor too. I taped around it just because I was worried about it leaking air in.
TECH Enthusiast
Joined: Apr 2009
Posts: 531
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From: Pocatello Idaho
If you haven't fixed the problem yet it sounds like you have some KR showing up. If you have a way to check for it that would help. If you have some KR it is most likely that you are running lean. I had what sounds like the same problem as you. I have a predator and noticed I was having a few degrees of it here and there. Not really consistent either. I ended up having a pretty lean condition which ended up being a vaccum leak. Just an idea.
