New owner, new issues.
#1
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Join Date: Feb 2017
Location: Hampton, VA
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New owner, new issues.
Hey everyone. I just bought a 99 T/A the other day and so far I've come across a few issues that need attention. I'm doing my own research as well but figured I'd post here in case anyone has some insight.
The first issue is I get some surging on acceleration, usually when I hit about 40 mph if I'm on the pedal just enough to maintain speed or go a bit faster the engine seems to surge and the RPMs will go up and down as well as exhaust note. Again, only when I'm barely on it, if I open the throttle up a bit more it takes off like normal. I'm assuming this has something to do with either air or fuel delivery.
Second is it seems like right around the same time i get the surging my car vibrates and makes a sound almost like what you would get if you went over rumble strips. This is also on acceleration. Idk if it means anything but the car has been upgraded to 4:10 gears and I believe a somewhat upgraded transmission.
The last one (for now) is a knock that I get when I tap the pedal. Kind of like You would when you rev match to downshift. It comes from the back somewhere under the backseat, possibly the diff. This one most likely won't get a solution on here but hey maybe someone else out there has experienced it.
Also, there's some pretty big tires on the back compared to the ones up front so the speedometer is way off. Is there a way to recalibrate without tuning it? I can only do so much with the tuner I have and writing different tire sizes isn't one of them.
Mods that I know of are as followed:
BBK SSI Intake
BBK TB
BBK Longtubes
SLP Lid Intake
Possible mild cam
Possible stall
4:10 gears
Full BMR Suspension (Extremely Stiff)
3 inch exhaust from headers back .
I've always been a WBody guy and I am New to the FBody world so I don't know too much about them, so any help is appreciated.
The first issue is I get some surging on acceleration, usually when I hit about 40 mph if I'm on the pedal just enough to maintain speed or go a bit faster the engine seems to surge and the RPMs will go up and down as well as exhaust note. Again, only when I'm barely on it, if I open the throttle up a bit more it takes off like normal. I'm assuming this has something to do with either air or fuel delivery.
Second is it seems like right around the same time i get the surging my car vibrates and makes a sound almost like what you would get if you went over rumble strips. This is also on acceleration. Idk if it means anything but the car has been upgraded to 4:10 gears and I believe a somewhat upgraded transmission.
The last one (for now) is a knock that I get when I tap the pedal. Kind of like You would when you rev match to downshift. It comes from the back somewhere under the backseat, possibly the diff. This one most likely won't get a solution on here but hey maybe someone else out there has experienced it.
Also, there's some pretty big tires on the back compared to the ones up front so the speedometer is way off. Is there a way to recalibrate without tuning it? I can only do so much with the tuner I have and writing different tire sizes isn't one of them.
Mods that I know of are as followed:
BBK SSI Intake
BBK TB
BBK Longtubes
SLP Lid Intake
Possible mild cam
Possible stall
4:10 gears
Full BMR Suspension (Extremely Stiff)
3 inch exhaust from headers back .
I've always been a WBody guy and I am New to the FBody world so I don't know too much about them, so any help is appreciated.
#2
TECH Senior Member
Hey everyone. I just bought a 99 T/A the other day and so far I've come across a few issues that need attention. I'm doing my own research as well but figured I'd post here in case anyone has some insight.
The first issue is I get some surging on acceleration, usually when I hit about 40 mph if I'm on the pedal just enough to maintain speed or go a bit faster the engine seems to surge and the RPMs will go up and down as well as exhaust note. Again, only when I'm barely on it, if I open the throttle up a bit more it takes off like normal. I'm assuming this has something to do with either air or fuel delivery.
The first issue is I get some surging on acceleration, usually when I hit about 40 mph if I'm on the pedal just enough to maintain speed or go a bit faster the engine seems to surge and the RPMs will go up and down as well as exhaust note. Again, only when I'm barely on it, if I open the throttle up a bit more it takes off like normal. I'm assuming this has something to do with either air or fuel delivery.
My guess would be the front 2 02 sensors, some can be finicky with LT headers. This will most definitely cause surging/jerking issues.
Second is it seems like right around the same time i get the surging my car vibrates and makes a sound almost like what you would get if you went over rumble strips. This is also on acceleration. Idk if it means anything but the car has been upgraded to 4:10 gears and I believe a somewhat upgraded transmission.
The last one (for now) is a knock that I get when I tap the pedal. Kind of like You would when you rev match to downshift. It comes from the back somewhere under the backseat, possibly the diff. This one most likely won't get a solution on here but hey maybe someone else out there has experienced it.
The noise could be the exhaust hitting the floor boards like above, could be lose suspension pieces (torque arm,rear control arms,panhard bar) the drive shaft u joints, or could be play in the rear end.
Also, there's some pretty big tires on the back compared to the ones up front so the speedometer is way off. Is there a way to recalibrate without tuning it? I can only do so much with the tuner I have and writing different tire sizes isn't one of them.
Mods that I know of are as followed:
BBK SSI Intake
BBK TB
BBK Longtubes
SLP Lid Intake
Possible mild cam
Possible stall
4:10 gears
Full BMR Suspension (Extremely Stiff)
3 inch exhaust from headers back .
I've always been a WBody guy and I am New to the FBody world so I don't know too much about them, so any help is appreciated.
BBK SSI Intake
BBK TB
BBK Longtubes
SLP Lid Intake
Possible mild cam
Possible stall
4:10 gears
Full BMR Suspension (Extremely Stiff)
3 inch exhaust from headers back .
I've always been a WBody guy and I am New to the FBody world so I don't know too much about them, so any help is appreciated.
#3
TECH Veteran
iTrader: (14)
Bump in the back is probably the 3" exhaust taping the axle or the lanyard support. I ran into that with my Corsa setup ages ago.
Knock up front could be a engine mount being g bad and allowing the engine to rock during the rev and letting the collector bang the floor board.
Surging could be due to a bad tune for the cam. A/c on when this issue arises?
With all the suspension work I'd look I to nailing down the surge before I get into the vibration if it only occurs in that condition. It would just be due to the weight transfer on the car with the surge.
Also the knocking you are hearing... Do you what kind of end joints the suspension parts have some of those can be rather noisey. Special if it's rod joints
Knock up front could be a engine mount being g bad and allowing the engine to rock during the rev and letting the collector bang the floor board.
Surging could be due to a bad tune for the cam. A/c on when this issue arises?
With all the suspension work I'd look I to nailing down the surge before I get into the vibration if it only occurs in that condition. It would just be due to the weight transfer on the car with the surge.
Also the knocking you are hearing... Do you what kind of end joints the suspension parts have some of those can be rather noisey. Special if it's rod joints
#4
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Location: Saskatchewan, Canada
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Any engine lights on when you get surging? Have you put a code reader on to see if there have been previous codes? I agree with JD_AMG about the O2 sensors - they can cause all kinds of issues but usually will throw a code of some sort.
Not to be an alarmist, but were the 4.10 gears done by a professional? It's easy to get an alignment out that could cause any number of sounds.
Good luck - hope you get this all straightened out.
Not to be an alarmist, but were the 4.10 gears done by a professional? It's easy to get an alignment out that could cause any number of sounds.
Good luck - hope you get this all straightened out.
#5
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Join Date: Feb 2017
Location: Hampton, VA
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Thanks for the responses guys. Glad to see that this forum actually offers help unlike the LS4 one.
I was able to pull a code from the car that has to do with the 02 sensor so that will be my first order of business getting that sorted out.
As far as the noises I'll have to check on the suspension and see if there's any contact points that shouldn't be there.
And with the work done. I didn't get any sort of paperwork on it, the previous owner bought it with most of it done and only added a few others like the gears wheels and exhaust. I have a shop nearby that a lot of LS guys go to so once I get the car registered and road legal I'll be taking it to him to QC it and get it tuned.
Hopefully this won't be too much of a headache.
I was able to pull a code from the car that has to do with the 02 sensor so that will be my first order of business getting that sorted out.
As far as the noises I'll have to check on the suspension and see if there's any contact points that shouldn't be there.
And with the work done. I didn't get any sort of paperwork on it, the previous owner bought it with most of it done and only added a few others like the gears wheels and exhaust. I have a shop nearby that a lot of LS guys go to so once I get the car registered and road legal I'll be taking it to him to QC it and get it tuned.
Hopefully this won't be too much of a headache.
#6
TECH Senior Member
You may have to experiment with different brands and have some extra tuning done as well, you could just luck out and replace them and be good to go, but they may throw a code again in a few thousand miles.
#7
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Weird, went to pull the code so I could do some research on it and there was no code to pull. The car had only been driven like 70 miles since PO bought it back in November and I didn't clear the code last time i pulled it so I'm wondering if it just needed a good drive (the 200 total mile trip to buy it) to shake off the dust. Still getting some odd readings regarding the EGR so I'll be looking into that as well.
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#8
TECH Resident
iTrader: (2)
The first issue is I get some surging on acceleration, usually when I hit about 40 mph if I'm on the pedal just enough to maintain speed or go a bit faster the engine seems to surge and the RPMs will go up and down as well as exhaust note. Again, only when I'm barely on it, if I open the throttle up a bit more it takes off like normal. I'm assuming this has something to do with either air or fuel delivery.
Second is it seems like right around the same time i get the surging my car vibrates and makes a sound almost like what you would get if you went over rumble strips.
THIS SOUNDS LIKE LUGGING. check the tune
Second is it seems like right around the same time i get the surging my car vibrates and makes a sound almost like what you would get if you went over rumble strips.
THIS SOUNDS LIKE LUGGING. check the tune