Strange acceleration problem
#1
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Strange acceleration problem
I just bought a 02 camaro, when I take off semi normal or to the floor or from a roll to increase speed the car will act like it looses power, bucks, and chugs. Let back off the throttle a bit and it smooths out. Step back into it and it will do it all over again. Feels like you are trying to drag a house behind you when it happens. Strange part if i drop it in low gear (automatic) and manually shift through the gears it will blow the tires off it through 3 gears feathering the throttle. It has a newly rebuilt tranny, a program, long tube headers, and 3 inch exhaust, with what appears aftermarket 390 gears. I'm thinking maybe a bad tune, but, not really sure. Any Ideas or suggestions would be great. Thanks.
Last edited by rollingmuscle; 01-01-2013 at 08:40 AM.
#2
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Have you pulled the intake off and checked the MAF or any of the intake components? Just a thought that something might be obstructing it. Are you getting an SES(service engine soon) light?
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No check engine light on. I just bought the car last knight so I have not tore anything apart. Was hoping for ideas or suggestions of where to start. I bought the car knowing of the problem, but figured it wasn't major since it ran so good when shifting it manually through the gears.
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As for the other issue, you could try cleaning the MAF. Dirty MAF wires can cause all kinds of driveability issues (and even some shifting weirdness with auto transmissions). It's a cheap and easy first step that can't hurt.
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I just ran out with it and put a few gallons of gas in it and the check gauges light went out. So, good call on that. Also, when the car was first cranked and cold it worked fine. As it started getting up to temp. the problem came back and worsened as it kept getting warmer. Last night when I purchased it, the guy I bought it from delivered it to my driveway so it was already warm. I'll check the MAF as suggested.
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Auto matic trans. If I manually shift through the gears though it will keep pulling. Runs real strong with no problems. It's only when I have the car in drive and letting it shift on It's own that I have the problem. If I ratchet through the gears It will keep pulling, so I don't think It's a fuel supply issue. When It's in drive It's any time you are trying to accelerate anything beyond 1st gear. Hard acceleration or just a passing type acceleration. If you just barely feather the throttle it does fine. Otherwise, pull it back manually and hold on.
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Auto matic trans. If I manually shift through the gears though it will keep pulling. Runs real strong with no problems. It's only when I have the car in drive and letting it shift on It's own that I have the problem. If I ratchet through the gears It will keep pulling, so I don't think It's a fuel supply issue. When It's in drive It's any time you are trying to accelerate anything beyond 1st gear. Hard acceleration or just a passing type acceleration. If you just barely feather the throttle it does fine. Otherwise, pull it back manually and hold on.
My guess is either a trans or trans tuning problem, or erroneous MAF readings. I would start with the MAF cleaning, since it's easy and free and is a good thing to do as part of a general tune-up process anyway.
#11
Sounds like a failing o2 sensor to me. Long tube headers loose a lot of heat out of the exhaust before it reaches the sensors so they might not be reading right. Also a failing o2 sensor will not always trip the check engine light.
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^ Only doing it in drive makes it really strange. Just diagnosed a bad o2 on my buddy's jeep and would run like *** intermittently, but would always clear up on WOT and was showing stuck in OL.
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I've got a guy that is going to test the program. He thinks it is in the shift setup in the computer with the changing of the gears in the rear. He's a knowledgeable programmer in the area. I will let everyone know what we find out when we check it out. He says it sounds like something with the the speed VS. what the computer is thinking it should be reading are not meshing with each other. Could be that when the gears were changed something wasn't entered rite or at all. He's thinking that's why shifting manually works, because that overrides the brain. I think it will be a good starting point. Heck, while we're at it, I'm gonna throw a cam, springs, retainers, and pushrods in it as well.
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Program was screwed up big time. Shift points were overlapping downshift and upshift along with other stuff. It runs great now. Whoever did the program before I bought it must have not known what they were doing.