why is my car hesitating?

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Jan 15, 2007 | 06:50 PM
  #1  
my car is Evo stage 4 with wastegate springs. it pulls hard at 1.2 boost all the way to 7000 rpm in 3rd gear. in 4th gear,WOT, it pulls until 5500 rpm, then hesitates and seems to stall. its not rpm limitor and the boost is only 0.9. the car feels like its stalling or starving for fuel. and.. it doesn't do it every time I open it up. here is an example from today. country road, I nailed it starting in 2nd gear, pulled hard until 5th gear. i'm doing 150, 5500 rpm and only .9 boost and it seems stalled there. ran out of road, so backed off

anyone understand what i'm describing? thanks
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Jan 15, 2007 | 06:52 PM
  #2  
Only .9 Boost in 5th? Why?

May be MAF?

May also be plugs.
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Jan 15, 2007 | 07:13 PM
  #3  
I bet its a MAF and possibly the Plugs....
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Jan 15, 2007 | 07:14 PM
  #4  
sounds like it needs plugs, mine did the same thing before changing them.
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Jan 15, 2007 | 07:24 PM
  #5  
Same thing on my Ruf Rturbo and put in plugs and all was well.

JCM
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Jan 15, 2007 | 07:25 PM
  #6  
I second the plugs or MAf issue. -Suman
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Jan 15, 2007 | 07:27 PM
  #7  
Plugs.... also ur TB may be shutting down....
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Jan 15, 2007 | 07:36 PM
  #8  
Quote: Plugs.... also ur TB may be shutting down....
True - You may be going into "Limp" mode!
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Jan 15, 2007 | 09:05 PM
  #9  
plugs? I only have about 12K miles on the entire upgrade, including the plugs. how many miles are plugs good for? I'll have my guy check the MAF. thanks guys
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Jan 15, 2007 | 11:19 PM
  #10  
My plugs had just under 20K on them. Porsche recommend plugs in stock TT at 30K.

JCM
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Jan 15, 2007 | 11:43 PM
  #11  
I'd say plugs first as well...do you have an upgraded FPR? What octane you running. Is it the same tank of gas?
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Jan 16, 2007 | 02:42 AM
  #12  
I would say plugs but its so weird how it doesnt happen in the lower gears first at WOT, hmm!
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Jan 16, 2007 | 07:24 AM
  #13  
Quote: I would say plugs but its so weird how it doesnt happen in the lower gears first at WOT, hmm!
martin,
its not weird... it did the same thing to me... usually ur not at full boost nor full load in lower gears... its only when u get in 4th.. sometimes top of the 3rd.... thats when u feel it...
I forgot if the Doc has upgraded WG springs.. if so.. there is ur answer... he probably ran too much boost and fowled the plugs.... maybe it was cold and the boost creeped up on him... as far as the .9 bars.. his TB shutdown and went to limp mode...
thats why I prefer tuning kits that offer the TB shutdown bypassed with the ability to controll the boost as well.
Imagine how hard it it to dial inn those WG springs such that they dont hit 1.3 bars yet give the max each and every time... now put the changing temps in the mix and there is ur problem... (colder= more boost... warmer=less boost).
just my opinion.
markski
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Jan 16, 2007 | 09:54 AM
  #14  
Quote: plugs? I only have about 12K miles on the entire upgrade, including the plugs. how many miles are plugs good for? I'll have my guy check the MAF. thanks guys
With a Stage 4 setup the plugs are not going to last 30K miles.
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Jan 16, 2007 | 01:16 PM
  #15  
Quote: martin,
its not weird... it did the same thing to me... usually ur not at full boost nor full load in lower gears... its only when u get in 4th.. sometimes top of the 3rd.... thats when u feel it...
I forgot if the Doc has upgraded WG springs.. if so.. there is ur answer... he probably ran too much boost and fowled the plugs.... maybe it was cold and the boost creeped up on him... as far as the .9 bars.. his TB shutdown and went to limp mode...
thats why I prefer tuning kits that offer the TB shutdown bypassed with the ability to controll the boost as well.
Imagine how hard it it to dial inn those WG springs such that they dont hit 1.3 bars yet give the max each and every time... now put the changing temps in the mix and there is ur problem... (colder= more boost... warmer=less boost).
just my opinion.
markski
I do have WG springs from evo. I usually see 1.2 bar at WOT, but have also seen spikes of 1.3 and even 1.4 for a millisecond. would that brief over boost foul my plugs? if my plugs are bad, does it make sense that the car runs perfect in 3rd gear, WOT, 1.2 boost? I don't have a problem until the top end of 4th or top end of 5th. thanks guys
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