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Hi everyone. I posted months ago looking for help with my car. 2007 cts 2.8. I have spent months trying to get this car going. It will start, run rough, then stall after about 5 seconds at most.
So far I have replaced the fuel filter, fuel pump, the throttle body, maf sensor, purge valve. I've been told to replace the crank sensor, so I guess thats next.
I had a throttle body sensor code, thats why it was replaced. New throttle body made no difference. Nothing thats been changed has made a bit of difference. This has been going on for 7 months. I tinker with it when I have time but now my other car has some structural issues so I really need the cts to run.
Any ideas?? Any thoughts are appreciated.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,672 Posts
Hi everyone. I posted months ago looking for help with my car. 2007 cts 2.8. I have spent months trying to get this car going. It will start, run rough, then stall after about 5 seconds at most.
So far I have replaced the fuel filter, fuel pump, the throttle body, maf sensor, purge valve. I've been told to replace the crank sensor, so I guess thats next.
I had a throttle body sensor code, thats why it was replaced. New throttle body made no difference. Nothing thats been changed has made a bit of difference. This has been going on for 7 months. I tinker with it when I have time but now my other car has some structural issues so I really need the cts to run.
Any ideas?? Any thoughts are appreciated.
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you could continue throwing miscellaneous parts at it -
and HOPE that something finally "sticks -
OR - you could actually DIAGNOSE the problem - then FIX it -

STEP #1 - ALWAYS - check for DTC's - Diagnostic Trouble Codes -

STEP #2 - POST the codes - EXACTLY as they are displayed -
include whether the codes are C-Current or H-History -
AND - include the code DEFINITIONS - as listed here -
 

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Discussion Starter #3
There are no codes, check engine light is not on and I have no way to get it scanned because everything is closed for covid.
I would obviously take the easy route if there were one 🤷‍♀️
 

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Discussion Starter #4
P0122 is the only code that ever came up. Changed the throttle body & nothing changed. Code is gone.
 

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2011 SRX Turbo
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69 Posts
P0122 often relates to the sensor in the accelerator pedal itself. You may want to test that.
 

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08 CTS 3.6, 83 Foxbody T-bird 5.0
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P0122 is the only code that ever came up. Changed the throttle body & nothing changed. Code is gone.
===========================
you could continue throwing miscellaneous parts at it -
and HOPE that something finally "sticks -
OR - you could actually DIAGNOSE the problem - then FIX it -

STEP #1 - ALWAYS - check for DTC's - Diagnostic Trouble Codes -

STEP #2 - POST the codes - EXACTLY as they are displayed -
include whether the codes are C-Current or H-History -
AND - include the code DEFINITIONS - as listed here -
Sorry to hear you wasted a lot of money on parts. First always check fuel pressure before replacing pump at the fuel rail. If it is below spec. then replace filter to see if it changes the pressure reading. If it is still below spec. then replace pump. Throttle body, will still start and run but not drive. You have a drive-by-wire system, meaning no throttle cable being used. So it will start and run. Idle? if the Idle air control was faulty (IAC) then it would start then shut down not run rough. Mass Air Flow (MAF) sensor will just throw a code not reading the amount of air going in, as going out which is monitored by the rear O2 sensor. It will shut down the engine after awhile. And set a code P0171 lean bank 1 or P0174 lean bank 2. Purge valve is only used after the engine has started then it opens to the intake to suck fumes stored in the charcoal canister from the fuel tank. (Emission only) Crank sensor, it either starts or it doesn't, no brainier there. What your describing is either worn spark plugs, coil pack not firing, or a bad intake leak (vacuum leak). If your car has over 125K miles, and the spark plugs have never been changed its a good chance there worn, also check the air filter if its dirty and clogged, then the engine is starving for air. An engine is just a large air pump with wheels, air goes in, and air goes out. Another possability, clogged (cats, exhaust side) preventing air from going out. just a few issues on working with large and small cubic inch air pumps with wheels. Hope this helps and, Good Luck.
 

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08 STS 1SG HUD ACC F55 AWD, 08 STS 1SG Platinum HUD ACC F55 RWD
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Check for an intermittent wiring problem to the throttle body. Corrosion, inside the insulation wire break, and others are hard to find.
 
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