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03-01-2009, 05:58 PM #1
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- Jan 2006
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blacker than wesleysnipes- 98' trans am
erratic idle and surging at low speed
Hey everyone
i installed a ls6 intake manifold two days ago. Well everything went according to plan...broke my oil pressure sending unit and swore more then a sailor. Well When i started my car up (98 trans am, no internals mods) I noticed erratic idle..the car would idle real low..the 500rpm range. The car never has stalled but gets close. When i let it warm up it will flucuate between 500 all the way up to 2k..however when its in park it ranges from 1k-2k..in gear drops to 500.
I unplugged my maf and the idle stopped searching so much and sounded good at a little under 1k...but then in neutral it was up to 1500..I read here that the IAC could be dirty. It was filthy but after i cleaned it and did a pcm relearn it still searches a lot..with terrible lag in low end throttle response and low end driveability and bad idle quality...any suggestions will be greatly appreciated
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03-01-2009, 06:17 PM #2
sounds like it might be s bad vacuum leak. did you plug the brake booster and heater control line back into the back of the manifold?
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03-01-2009, 06:58 PM #3
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03-01-2009, 07:20 PM #4
- Join Date
- Jul 2007
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- Chicago IL
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- 140
Pewter- 2000 A4 WS6
I know its a totally diffrent beast but when I had my srt4 I had damn near the same problem and It was a mainfold gasket leak. Sounds like a gasket and or vaccumm leak... spray down around the intake and see if idle changes.....
Jeff
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03-01-2009, 07:46 PM #5
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- Jan 2006
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- 11,770
blacker than wesleysnipes- 98' trans am
hmm we didn't have a inch pound torque wrench with us so we snugged them..i wonder :| what do i spray by the gaskets?? maf cleaner( it is safe for electronics etc.
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03-01-2009, 09:21 PM #6
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03-01-2009, 10:51 PM #7
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- Apr 2007
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- Forest Lake, MN
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- 44
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- 488
maroon- 2000 Z28
Tune it and mess with the TPS. Looks like the same problems I had before and the tune fixed it.
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03-02-2009, 12:32 AM #8
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- Oct 2007
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- Beaver Dam KY
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- 7,745
79 T/A -91 Firebird- 1998 Trans Am -Oynx Black
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03-02-2009, 06:58 AM #9
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- Jan 2006
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- Shepherd, Michigan
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- 36
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blacker than wesleysnipes- 98' trans am
hmm i am 98% sure its a vacuum leak in the brake booster line to the manifold..however if i change that out and still no change..i will replace the tps...how much is a tps ? and does anyone know the size of hose for the brake booster so i can replace if needed ?
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03-02-2009, 07:00 AM #10
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- Oct 2007
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- Beaver Dam KY
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- 7,745
79 T/A -91 Firebird- 1998 Trans Am -Oynx Black
I do believe it is 1/2 inch. TPS brand new with warranty was 27 here.
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03-02-2009, 07:34 AM #11
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03-02-2009, 02:26 PM #12
- Join Date
- Oct 2007
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- Beaver Dam KY
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- 7,745
79 T/A -91 Firebird- 1998 Trans Am -Oynx Black
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03-03-2009, 06:16 PM #13
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- Shepherd, Michigan
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blacker than wesleysnipes- 98' trans am
ok it's a vacuum leak and its coming from the protruding fitting on the back..where the hvac and brake booster go into...its gasket is showing ..so my question is how do i remove it/put it back on.. :S
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03-03-2009, 06:20 PM #14
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- Oct 2007
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- Beaver Dam KY
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79 T/A -91 Firebird- 1998 Trans Am -Oynx Black
Isnt that where the map goes?
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03-04-2009, 05:36 AM #15
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03-04-2009, 05:36 AM #16
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- Jan 2006
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blacker than wesleysnipes- 98' trans am
on one side there is alot of play ..like its about to fall out...and i can see the orange gasket on that side (the brake booster side)
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06-30-2010, 04:47 PM #17
how the hell do u guys see back there. even a mirror sucks.
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06-30-2010, 07:03 PM #18
If the orange gasket that belongs to the MAP sensor is worn it can leak. Was that a new intake or used? Make sure that the plastic elbow piece is not actually leaking or it has a crack.
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07-01-2010, 09:34 AM #19
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- 36
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- 11,770
blacker than wesleysnipes- 98' trans am
woah old thread. well it was used and i found out it had a small crack in it...more than likely from me over torquing it. so i jb welded it and it is fine. however i would like to change out the map sensor one of these days. most all of the sensors are 12-13 years old and have close to 100k on them.
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07-01-2010, 09:35 AM #20
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