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2000 S40 rough Idle at Stoplights - stalls sometimes,Rich Fuel Exhaust

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Old Jul 2, 2023 | 11:27 PM
  #1  
S40Mystery's Avatar
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Default 2000 S40 rough Idle at Stoplights - stalls sometimes,Rich Fuel Exhaust

Ok, explaining all this will take a moment...
Location - 3260 feet elevation, Currently low to mderate humidity, morning temps around 70 afternoon temps around 90+

2000 S40, 140k miles, Does not use oil, Gas mileage in city averages about 19 mpg HWY about 23, 1.9l Turbo with AT and NEW PARTS: Coils/wires, Sparkplugs, Rebuilt and tested Fuel Injectors, Motor mounts, Fuel Pressure Sensor, MAP Sensor, MAF sensor, Cam Sensor, Throttle position sensor, Thermostat, Temp Sensors, Both Oxygen Sensors, Turbo Boost Sensor, PCV Box & lines, Air Filter...and probably more I've forgotten...but you get the gist.
I have always used Mobile 1 synthetic 10-30 High Mileage oil, Wix premium filters, Lucas or Chevron fuel injector cleaning solution every 2-5k miles. 90-91 octane fuel.

Situation: Currently various codes that do not make sense as component replacements (e.g. MAP sensor replaced twice, Atmospheric Sensor 3 times, etc.) did not resolve codes.
Current ECM codes are as follows:
  • 0D - Boost Pressure sensor (signal too low)
  • 4D - Misfire which Damages Catalytic Converter - faulty signal
  • 0B - Atmospheric Pressure sensor - Signal too low
  • 44 - Missfire, Emmision Level
  • P0302 (Cylinder 2 Misfire detected)
  • P1106 (MAP Sensor performance - problem or signal out of range)
Drivability issues:
  • Intial startup in morning is rough idle with VERY rich gas smell in exhaust
  • Allow to warmup for 5-10 minutes before driving.
  • Typical Idle RPM is around 720
  • Some days, when accellerating from a stopped position, depressing gas pedal and the engine will lag, and further depressing the gas pedal (e.g. 1/2 way down+) does not induce accelleration and sounds a bit "bogged down", and then suddenly the accelleration takes hold and the car takes off with significant speed. When attempting to clear the bogging, and depressing the gas pedal to full throttle, still bogged and then takes off. Throtle is functional and no issues with the throttle body assembly.
  • Coming to stop at a traffic light can experience idle whereby it increases and decreses in a wave-like function, up 100-200 RMPS, down 100-200 rpms, up...down...up...down.... Other times the idle stumbles and drops 200+ RPMs with rough idle. Must shift into Neutral to depress gas pedal to maintain idle from stalling engine.
  • I had cleared all codes and when engine is fresh from cleared codes...will run with issues all over the map unitl the car learns the new values from driving/sensors.
  • After ECM "learns" new settings, and egnine is performing well...simply pressing the "S" or "Sport" button for the transmission and ECM mode will cause all the above problems to return with a vengence.
  • Running the air conditioner on Freeway only engine performs well, very responsive to slightest touch of the gas pedal...but as soon as exiting freeway and shutting off the AC...car will run like garbage as above with idel problems, sluggish then bat-out-of-hell accelleration, etc.
  • Sometimes after high accelleration runs or freeway runs, strong sulfer smell from Catalytic converter...

ANYONE have ANY idea what might be going on?
Biggest issues:
  • Unacceptable idle issues at various times - stopping at stoplights, initial startups, etc. - rough idle, wave-like up/down idle speed fluctuations
  • Unacceptable accelleration performance with bogged-down accelleration and then significant bat-out-of-hell accelleration
  • Rich gas smell in exhaust, especially at startup idle for 5-10 minutes
  • No ability to use "S" mode nor Airconditioning as will severly affect engine issues
any chance Catalitic converter is bad or minor leak in exhaust line would cause such issues?
Any help you can think of would be GREATLY appreciated!
God Bless,



 
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Old Jul 4, 2023 | 11:43 AM
  #2  
habbyguy's Avatar
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From: Mesa, AZ
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When I see a shopping list like the one for your car, I have to ask whether all that was in response to the symptoms you're seeing now, or if the current problems happened after doing all those swaps.

Thing is, it's not at all uncommon for new parts to induce "new and exciting" problems, whether due to off-brand / no-name parts, or even counterfeit parts (coils being one of the worst). But any sensor that's critical to the operation of the engine has to be suspect (I see you've re-swapped some of them looking for the issue).

I do remember that my V70 T5 had similar issues when the intake pipe came slightly loose.
 
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Old Sep 13, 2023 | 04:48 PM
  #3  
cgrand's Avatar
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I'm having similar symptoms, did you ever figure out what was causing this issue?
 
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