Idle surge and weird noise
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Teching In
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Idle surge and weird noise Hi new to the forum, so I have a 2001 Trans am ws6 with an LS2 swap in it. It was all done by the previous owner. Apparently it has a M303 Cam in it? Idk if any of you have heard of it but that’s what he said. It also has 3 inch headers and a FAST intake manifold, a 3200 rpm stall I believe, and a 12 bolt with 4.88 gears .The car starts good but the idle surges from about 700 rpmall the way up to 1500 rpm and sometimes it doesn’t move from 900rpm and stays consistent. I unplugged the Throttle position sensor and it went into limp mode, but the idle dropped to 750 rpm and ran near perfect other than the fact that it won’t go past 4k rpm. I replaced the TPS and nothing. So I was thinking maybe it just needs a good tune? Also it has a very strange clunking noise and feel that happens when i coast around 25 mph and I have no clue what it is. I know that isn’t specific at all but I’ve literally never felt something like it before. But it goes away with a bit of gas or if I go into neutral.
TECH Junkie
Joined: Nov 2013
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From: White Bear, Mn
Next time you feel the clunking, keep your speed with the gas but gently push the break at the same time. This will unlock the converter. Im guessing the converter is locking at to low off rpms which is a time issue
Thread Starter
Teching In
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Thread Starter
Teching In
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TECH Junkie
Joined: Nov 2013
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From: White Bear, Mn
In my last post I meant it's a tune issue. If the problem is solved by gently pushing the brake, in turn unlocking the converter, then it can only be fixed in the tune.
I myself have mine tuned so it will not lock in 1st, 2nd or 3rd. Only in 4th gear and only above 55 mph.
I myself have mine tuned so it will not lock in 1st, 2nd or 3rd. Only in 4th gear and only above 55 mph.
Thread Starter
Teching In
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In my last post I meant it's a tune issue. If the problem is solved by gently pushing the brake, in turn unlocking the converter, then it can only be fixed in the tune.
I myself have mine tuned so it will not lock in 1st, 2nd or 3rd. Only in 4th gear and only above 55 mph.
I myself have mine tuned so it will not lock in 1st, 2nd or 3rd. Only in 4th gear and only above 55 mph.
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TECH Junkie
Joined: Nov 2013
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From: White Bear, Mn
If your car really does have 4.88 gears (way steep for a A4) then I would not have it lock up in 1st, 2nd or 3rd. Just 4th maybe around 40-45 mph. If it is indeed your converter locking up at low rpms this will take care of a lot of drivability issues. Im assuming this is a 4l60e?
Try what I explained in keeping the speed consistent when you feel the shudder and very lightly press the break and see if it goes away
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Teching In
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Doing so keeps the converter from constantly locking and unlocking in city driving along with lugging the motor with cammed cars causing some drivability/ bucking issues at way low rpms (which is what happens when the converter locks at low speeds).
If your car really does have 4.88 gears (way steep for a A4) then I would not have it lock up in 1st, 2nd or 3rd. Just 4th maybe around 40-45 mph. If it is indeed your converter locking up at low rpms this will take care of a lot of drivability issues. Im assuming this is a 4l60e?
Try what I explained in keeping the speed consistent when you feel the shudder and very lightly press the break and see if it goes away
If your car really does have 4.88 gears (way steep for a A4) then I would not have it lock up in 1st, 2nd or 3rd. Just 4th maybe around 40-45 mph. If it is indeed your converter locking up at low rpms this will take care of a lot of drivability issues. Im assuming this is a 4l60e?
Try what I explained in keeping the speed consistent when you feel the shudder and very lightly press the break and see if it goes away
An IAC idle air control valve can cause your idle surge condition. You’ll hear air surging with the valve shifting/can’t make up it’s mind what the correct setting should be. eBay sells cheapies (about $25 delivered), if you’d like to try that route.
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Teching In
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I tried that too, and honestly the surging reduced a bit but it’ll still do it.
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Thread Starter
Teching In
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Doing so keeps the converter from constantly locking and unlocking in city driving along with lugging the motor with cammed cars causing some drivability/ bucking issues at way low rpms (which is what happens when the converter locks at low speeds).
If your car really does have 4.88 gears (way steep for a A4) then I would not have it lock up in 1st, 2nd or 3rd. Just 4th maybe around 40-45 mph. If it is indeed your converter locking up at low rpms this will take care of a lot of drivability issues. Im assuming this is a 4l60e?
Try what I explained in keeping the speed consistent when you feel the shudder and very lightly press the break and see if it goes away
If your car really does have 4.88 gears (way steep for a A4) then I would not have it lock up in 1st, 2nd or 3rd. Just 4th maybe around 40-45 mph. If it is indeed your converter locking up at low rpms this will take care of a lot of drivability issues. Im assuming this is a 4l60e?
Try what I explained in keeping the speed consistent when you feel the shudder and very lightly press the break and see if it goes away
TECH Junkie
Joined: Nov 2013
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From: White Bear, Mn
Have it lock in 4th and only above about 45 mph and you will not feel any shuddering/lugging.