93SixtySpecial Posted November 14, 2012 Report Share Posted November 14, 2012 I decided to make this a new thread from my fuel filter one. After cleaning the throttle body and IAC, I still have the same issue. My idle is better though . It will only surge when it is in closed loop or fully warmed up and the stalling happens when it is warmer outside and both of these only happen around 25-40mph range. I'm not exactly sure on the range, but it's around there. The stalling seems to occur when coasting and it seems to be for some reason when going downhill (could be a coincidence). There are no codes. I have a hunch, I have no idea if I'm on the right track or not. I have a very high pitch whistle noise coming from the passenger side of the engine. I can't pin point where it is, but the noise is very prominent when the engine is cold (but not all the time) and you can't hear it when it's warm. Could it be a vacuum leak somewhere like an intake? I don't have a rough idle though. -Dusty- 2006 Cadillac DTS Glacier Gold Tri-Coat with 175,000 miles 1993 Cadillac Sixty Special Gold Mist with 185,000 miles Link to comment Share on other sites More sharing options...
PAUL T Posted November 14, 2012 Report Share Posted November 14, 2012 Check for a vacuum leak. I know in a 2000 and up there is a vacuum line coming out of the intake manifold on the passenger side. It was behind the power steering pump, it was very hard to see. Check the PCV valve. Check intake bolts to see if they are tight. Link to comment Share on other sites More sharing options...
BodybyFisher Posted November 14, 2012 Report Share Posted November 14, 2012 The high pitched whistle coming out of the passenger side of the engine is due to the over pressurization valve in in the intake leaking I believe, its behind the power steering pump. i am not sure if you can purchase a replacement valve, but look into it. Hopefully you dont need to replace the intake. I think rock had this problem if i recall. do a search on over pressurization valve there is info in the archives, I think I posted photos also This leak will cause a lean mixture and typically unless its not too bad yet you will get P0171 and P0174 both bank lean codes... if it is intermittant it will definately impact the idle when its actively leaking The valve is there in the event there is a backfire in the intake to prevent the NYLON 66 intake from blowing up and potentially hurting someone with schrapnal... Do us a favor if you find a good thread on this in the archives, post a link to it here to provide info on this for future readers, thanks Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
KHE Posted November 14, 2012 Report Share Posted November 14, 2012 Hopefully, the surging is not the beginning of the P0741 TCC code... Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
93SixtySpecial Posted November 16, 2012 Author Report Share Posted November 16, 2012 Don’t you dare say that! You’ll jinx it! I’ve had 3 out of 6 Caddys with the P0741 code and it’s a miserable code to live with. This one doesn’t have it…yet. It has been in the back of my mind though because it’s in the same range of my other 99 that had the P0741 with the surging. This one gets great mileage though so I’m hoping it’s a fuel/air or ignition issue. This surge is a little bit more “random” than my last 99. This one has larger surges, near stall surges and sometimes it does stall. I know that fuel/air and ignition issues show their ugly faces under light loads so I’m hoping that’s what this is. http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/142334-whistling-pressure-relief-n-intake-manifold.html I found this link so it looks like I can get the valve ($23 on gmpartsdirect.com). I'll do some checking for vacuum leaks and see if the noise is coming from the valve and replace it if necessary. We’ll start there and hopefully some issues will be fixed. -Dusty- 2006 Cadillac DTS Glacier Gold Tri-Coat with 175,000 miles 1993 Cadillac Sixty Special Gold Mist with 185,000 miles Link to comment Share on other sites More sharing options...
Texas Jim Posted November 16, 2012 Report Share Posted November 16, 2012 One way I have listened and tried to pin point a vacumm leak is... Take a piece of heater hose about 3 foot long... put an earplug in one ear to cut out outside noises...hold the heater hose to your "OTHER" ear and move the end of it around where you suspect the leak to be. It sounds stupid... but it works... Link to comment Share on other sites More sharing options...
93SixtySpecial Posted March 27, 2013 Author Report Share Posted March 27, 2013 UPDATE: Sorry it’s been a while since I’ve been on here, but I decided to wait it out and see if I got a code and I sure did. I got P0404. It was the EGR as I suspected. Stupidly, I purchased one off of eBay instead of just cleaning it. Not sure why, but that time has come and gone. Anyway, the one I ordered I was told it was Delphi, but I don’t see any indication that it was when I received it. It ran smooth as butter for 1300 miles, but started to surge, stall, and sputter worse than before. Sure enough I got the P0404 code again. I contacted the seller and they sent me another one and that one worked well for only 400 miles before is started to do it again still worse than the original time. Am I just having bad luck with EGRs or is there something else causing this situation? -Dusty- 2006 Cadillac DTS Glacier Gold Tri-Coat with 175,000 miles 1993 Cadillac Sixty Special Gold Mist with 185,000 miles Link to comment Share on other sites More sharing options...
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