2000 Saturn L200 High Idle, No Power. DTC: P0300/P0171/P017

Tiny
ROADRUNNER_007
  • MEMBER
  • 2000 SATURN L200
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 201,400 MILES
OK, I'm working on a 2000 LS2 V6-24v auto.
I pulled the following dtc's: P0300/P0171/P0174/P0154.

The engine when cold will crank and start and go straight to about 2000 rpm's and then die about 2-3 seconds later. If this process is repeated 6-8 times, the engine will continue to run while misfiring and idling at about 2000. After a few minutes the rpm's will rise to about 3000 and during this time most of the misfiring will subside. Punching the gas pedal does nothing, but putting it in gear brings the idle down to about 900-1200. At operating temp. It seems to idle fine but when driven has no power on demand, pushing down hard on the pedal will cause the engine to choke and stall out but it wont die. Using light pressure on the pedal you can build up speed and get up to 70mph. At those speeds it drives smooth with an occasional jerk here and there along with the tach dropping or rising at the same time as feeling the jerk/stutter. Seems as if you push the pedal down more than 25%, it chokes out.

Should I be looking for an intake vacuum leak on the right side (bank 2) of the engine based on these codes or should I be testing the O2 sensor and its connections? I wanna say the sensor is not in play during open loop so the high rpm's are the cause of a vacuum leak but the P0154 (no activity bank 2, sensor 1) has me confused. Can a major vacuum leak cause an O2 sensor to put out a signal that is so far to one side of its value that it is seen by the ECM as no activity? Or is there possibly two problems here?

Thank you so much in advance!
Friday, December 4th, 2009 AT 1:44 PM

7 Replies

Tiny
DOCFIXIT
  • MECHANIC
  • 18,828 POSTS
Check fuel pressure 41-48 psi. Yes exhaust or intake leak can be a factor
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Friday, December 4th, 2009 AT 3:10 PM
Tiny
ROADRUNNER_007
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Fuel pressure at rail held about 48psi from start through warmup and off. Found intake leak in pleats of intake downstream from MAF and major coking in pcv hose. Repaired & cleaned, now engine starts and dies and wont stay running at all. However if you unplug the MAF, cold engine starts and runs fine, around warmup starts running rough. Plug in MAF and engine dies, restart and it dies, unplug it and engine runs again.

Q: Is this definately the MAF?
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Monday, December 7th, 2009 AT 1:54 AM
Tiny
DOCFIXIT
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171 and 174 shows engine very lean both banks so what ever is fault is leaning out engine. Did you replace air plenum? Did you clean MAF with appropiate MAF cleaner? Clear codes and see what resets.
Let me know
Will be off line till Thursday
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Tuesday, December 8th, 2009 AT 8:39 AM
Tiny
ROADRUNNER_007
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Yep, replaced the 3" pleated intake hose, cleared PCV hose (clogged coking) and cleaned MAF with electrical cleaner (spray), noticed a difference in engine performance after, wont idle high or at all anymore, just starts normal and dies. The only way to warmup engine is to unplug MAF which will pull P0102 of course, and also P0113, P0405. If I pull the pleated intake hose off the TB and position it aside, leaving everything else hooked up and the MAF plugged in, the engine will start and run, but as soon as I start to reposition the pleated intake hose back over the TB, the engine will die, its just about the time air is being drawn past the MAF. Now, if all intake hoses are connected and I unplug the MAF, engine will run but as soon as MAF is plugged in the engine dies. When I first cleaned the MAF I noticed a large amount of debris stuck to it, the air cleaner was not seated or locked and intake tubes and clamps were all loose. I think it just got contaminated

What do you think, would you go with the MAF?
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Tuesday, December 8th, 2009 AT 4:48 PM
Tiny
DOCFIXIT
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If MAF that contaminated then yes replacement is good idea. Check voltage on terminal #4 gray wire if 4-6 then signal to PCM good.
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Thursday, December 10th, 2009 AT 9:23 AM
Tiny
ROADRUNNER_007
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Signal too high. Replaced the MAF, engine runs great! Thanks so much Doc.

This site is awesome, thanks 2carpros to all the staff & members! Keep up the great work, its very much appreciated.
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Friday, December 11th, 2009 AT 2:59 AM
Tiny
DOCFIXIT
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Hi roadrunner
Good work you gave good info that helped to solve fault. Come back again and tell a friend
Doc
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Friday, December 11th, 2009 AT 9:10 AM

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