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Discussion Starter #1
As of recent the car seems to be suffering from a lost of power, it feels marginally worse than the it feels during the 95+ degree days in the heat of the summer. The only codes that are evident are Cat eff. and the all to familiar SAI.

Within the last 7500 miles all new CPS, pre-cat O2 sensors, oil seperators, coils and plugs. Any ideas gurus?
 

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May I be the first to suggest MAFs? Did you try the MAF test to see what you are getting. I would also check the cats - plugged cat = bad
 

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TPS and fuel pressure regulator. Also you might consider opening up the plenum and check on your vacuum lines, fuel lines..etc.
 

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the cat code would be my first guess that they may be clogged and curling your exhaust flow robbing power
 

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Discussion Starter #6
I shouldve mentioned that I have 200 cel cats which are triggering the forementioned code and new fuel pump, fuel regulator and MAFs within the last 10k miles.

T will try the TPs reset to see if that helps
 

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Are you getting B2 and B3 or just B2 or B3 ?
 

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I would suggest for the ludicrously low prices you can get the genuine Bosch o2 sensors on Amazon, in the USA (they won't ship to us in the UK), that you get 2 post cat 02 sensors...after checking for any cracks on all 4 o2 sensor bungs, and all electrical connectors too.

Also as Mamsterla mentions, MAFS are looking pretty suspect, even though any associated erroneous fuelling codes would more likely be exhibited as some from of pre cat o2 sensor codes and/or fuel control codes like 90 and 91.

Good Luck
 
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Discussion Starter #10
Thanks but I was under the impression that even if the post cat o2 sensors have gone "bad" I still wouldnt feel a difference in performance, I definitely could be and probably am wrong though....

Im leaning towards a mysterious vaccum leak or TPS. I will run out during lunch and check the o2 bungs
 

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Thanks but I was under the impression that even if the post cat o2 sensors have gone "bad" I still wouldnt feel a difference in performance, I definitely could be and probably am wrong though....

Im leaning towards a mysterious vaccum leak or TPS. I will run out during lunch and check the o2 bungs
Vacuum leaks woudl lead to running lean condition, which will definitely be flagged up, heavily agressive +VE fuel trimming.

TPS would most likely give you a code if it was so gone, that its making you car feel flat. No arguments its better to refresh these though, just don't see it as your current issue, especially without a TPS code.

I could also be wrong ! But telling me what you have I would look at the the post cat o2 sensors. If your DME is telling you of fault codes, B2 and B3, it would be a brave man to say that this will have ZERO impact on how the DME will react. It may or may not. I think not, but at $70 dollars or so for a pair of new genuine ones, I know what I would be doing. FYI : I have not changed my post cat o2 sensors for new ones, and I have pretty much changed out everything else, including being on my second set of pre cat 02 sensors in 40K Miles.

Good Luck
 
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Al-x - I agree that post cat O2 would not impact the running of the car. Get into the secret menu and do the MAF fuel flow test. If you cannot get above 120, look and see if the MAFs got dirty. Are you running CAI or something like that? Some air filters like K&N have a history of fouling the MAFs. Given the rest of your repairs, I would check this out first.
 
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B2 and B3 is a direct result from your 200 cell race cats.... I have had My setup for a few years and always get these codes... cold weather and short warm ups help speed up the fault...their are a few solutions... have a peake reader onboard at all times- I do.. get some software ex. Powerchip and flash it after smog or inspection to turn off rear O2s or do what I did but thats a PM thing...
 

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Discussion Starter #14
B2 and B3 is a direct result from your 200 cell race cats.... I have had My setup for a few years and always get these codes... cold weather and short warm ups help speed up the fault...their are a few solutions... have a peake reader onboard at all times- I do.. get some software ex. Powerchip and flash it after smog or inspection to turn off rear O2s or do what I did but thats a PM thing...

Thanks Fizzle thats what I thought, Currently I have AA software but will be changing to Powerchip after I do the rod bearings. I just tried the TPS reset to no avail. Tuesday I have an appointment to get it smoked and I will check the MAFs also then. Its just frustrating with this damn car. I bought my wife an 150k mile 993 a couple of years back and didnt have a 1/4 of the problems I am having with this damnm thing. Labor of love I guess.........
 

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Al-x - once it is sorted out you will really enjoy it. Honestly, once it is locked in and you figure out the problem, the car should be a blast. Stick in there - they stay sorted once you fix the underlying issue.
 

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Discussion Starter #16
Come to think of it I did swap to oiled K&Ns when I did the front "ram air" tubes and brake ducts. May be the MAFs, can someone direct me to the MAF test ?
 

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ive had MAFS die under 10k miles so it is possible
 

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Discussion Starter #19
Just an update, it is indeed my MAFs. 95-101 readings under WOT @ 6500 RPM in second gear. If it hasnt been mentioned before oiled air filters are no bueno for these cars
 

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Just an update, it is indeed my MAFs. 95-101 readings under WOT @ 6500 RPM in second gear. If it hasnt been mentioned before oiled air filters are no bueno for these cars

Sounds plausible to me.

But don't forget you can have 100% brand new MAFS, and low MAF numbers due, to advers Fuel Trims, which are compensating for an issue.
 
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