carl425 Posted August 12, 2005 Report Share Posted August 12, 2005 Hmmm, my 99 STS is stalling once or twice a day when I come to a stop. It's running beautifully otherwise. Starts right back up, idles decent, no misses or hitching, etc... Any thoughts? I went through the code list today on the OBD and there were a bunch of PCM codes. I went back in the house to get a pad and paper and my 5 year old shut the key off when it got to "CLEAR ALL CODES?" and it did. So now I have to drive again and see if it will set new codes. Just wondering if anyone else has had this paritcular problem??? Lrac Link to comment Share on other sites More sharing options...
Scotty Posted August 12, 2005 Report Share Posted August 12, 2005 Try disconnecting the battery and let the system go through a relearn. You might clean your battery terminals while you are at it. You might also try cleaning the throttle body and plate with GM upper engine cleaner, don't get a lot of cleaner down the throat, use a tooth brush and make sure you clean the rear of the plate and throat good. About a week ago mine was rough at a stop light or two like it wanted to stall and it just cleared up.. No codes. There are so many things that can cause your problem, watch for codes. Mike Link to comment Share on other sites More sharing options...
JasonA Posted August 12, 2005 Report Share Posted August 12, 2005 Without the benefit of codes, I'd suggest searching the board for "crank position sensor" or "crankshaft position sensor". It sounds like one of the common failure modes for one of those sensors. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
Bill K Posted August 12, 2005 Report Share Posted August 12, 2005 With mine it was the EGR valve. A good cleaning cured the stalls. Link to comment Share on other sites More sharing options...
OynxSTS Posted August 12, 2005 Report Share Posted August 12, 2005 I went through the code list today on the OBD and there were a bunch of PCM codes. I went back in the house to get a pad and paper and my 5 year old shut the key off when it got to "CLEAR ALL CODES?" and it did. So now I have to drive again and see if it will set new codes. When working on a problem, clearing all the codes is not a bad place to start... Drive the car untill it stalls again and then pull your codes... This way you only get the new codes that related directly to your stall. If it stalls and you don't get any codes, As Scotty suggests, clean your throttle body, I would add remove and clean the Idle air bypass while your at it... Looking at the throttle body from the driver side of the car, it is on the left side of the throttle body. There are two gadgets there the bottom one is the TPS... The top one is the one you want to clean. If this doesn't help, then tackle the EGR Valve then finally the Crank Sensor. Though ussually the EGR and the Crank Sensor will throw a code... PS your 5 year old did more than turn the key off... He must have been watching you.. Because you need to press the on/off button once more to clear the codes... Mine are 4 and 6 very cute at this age! Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
bigjayzway Posted August 13, 2005 Report Share Posted August 13, 2005 With mine it was the EGR valve. A good cleaning cured the stalls. DITTO! Big Jay Life is too short to grow up! Link to comment Share on other sites More sharing options...
Scotty Posted August 13, 2005 Report Share Posted August 13, 2005 I went through the code list today on the OBD and there were a bunch of PCM codes. I went back in the house to get a pad and paper and my 5 year old shut the key off when it got to "CLEAR ALL CODES?" and it did. So now I have to drive again and see if it will set new codes. When working on a problem, clearing all the codes is not a bad place to start... Drive the car untill it stalls again and then pull your codes... This way you only get the new codes that related directly to your stall. If it stalls and you don't get any codes, As Scotty suggests, clean your throttle body, I would add remove and clean the Idle air bypass while your at it... Looking at the throttle body from the driver side of the car, it is on the left side of the throttle body. There are two gadgets there the bottom one is the TPS... The top one is the one you want to clean. If this doesn't help, then tackle the EGR Valve then finally the Crank Sensor. Though ussually the EGR and the Crank Sensor will throw a code... PS your 5 year old did more than turn the key off... He must have been watching you.. Because you need to press the on/off button once more to clear the codes... Mine are 4 and 6 very cute at this age! You learned me something Onyx... I had not heard of the Idle Air Bypass before, I'll be cleaning mine ASAP.... Thx.. Mike Link to comment Share on other sites More sharing options...
adallak Posted August 14, 2005 Report Share Posted August 14, 2005 With mine it was the EGR valve. A good cleaning cured the stalls. It means the EGR valve did not close when it was supposed to (because of deposits obviously). The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
OynxSTS Posted August 14, 2005 Report Share Posted August 14, 2005 You learned me something Onyx... I had not heard of the Idle Air Bypass before, I'll be cleaning mine ASAP.... Thx.. Mike By the way GM did a nice design on the bypass valve. You can re&re it as many times as you want as it is sealed with an O ring not a paper gasket.. Take care cleaning this as it is an electrical gizmo with a rubber tip… Some of the more aggressive cleaners will eat up the rubber.. Read the label, you should be OK with GM upper engine cleaner…Or Gas works too! Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
carl425 Posted August 27, 2005 Author Report Share Posted August 27, 2005 This is why I love this board so much. You guys are THE source when it comes to problems with these mighty machines. I've tried cleaning the throttle body but didn't get back to a computer (I'm stationed in Germany now and internet access is NOT as prevelant as I'm used to...) to see about the gadget above the TSP. So I'll try cleaning that next and the EGR. I wish new EGR's weren't so expensive, I'd just throw a new one on. I have looked for codes after it stalled again multiple times and there weren't any concerning the powertrain. So whatever it is, it's not setting a code. I did have one AMP U1064 that I see is a disconnect with the DIM. I think I'm having some stereo amplifier problems now, guess I'll be listening closer to that too... Does anyone have a good P/N for motor mounts for a 99 STS? Another little project on my to-do list... Thanks again to everyone for all the advice. CRP Link to comment Share on other sites More sharing options...
lack34 Posted September 2, 2005 Report Share Posted September 2, 2005 Hello, I'm not sure if you got the problem repaired yet, but I had the exact same problem about a year ago....my 95 SLS would stall when I came to a stop and it turned out to be the Fuel Pressure Regulator, a quick and easy fix. Link to comment Share on other sites More sharing options...
carl425 Posted September 6, 2005 Author Report Share Posted September 6, 2005 Hmm, I've replaced that once before and it is indeed a quick and easy fix. This time I'm not experiencing any of the troubles I had last time when it was a FPR. At that time it cranked for a long time before starting but ran fine when running. I may just change it again anyway, because I have now tried everything that everyone on this topic has suggested (still no codes, BTW for any of you who are following) and it hasn't cured the problem. I'm up to trying anything at this point... CRP Link to comment Share on other sites More sharing options...
Rickster Posted February 12, 2006 Report Share Posted February 12, 2006 Hmm, I've replaced that once before and it is indeed a quick and easy fix. This time I'm not experiencing any of the troubles I had last time when it was a FPR. At that time it cranked for a long time before starting but ran fine when running. I may just change it again anyway, because I have now tried everything that everyone on this topic has suggested (still no codes, BTW for any of you who are following) and it hasn't cured the problem. I'm up to trying anything at this point... CRP So Carl, what has transpired since Sept. Did you get it fixed? 2001 STS Mettalic Otter Grey, Black Leather, 213,000 kilometers - miles - ? Still running strong! Link to comment Share on other sites More sharing options...
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