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left bank lean/right bank lean,any suggestions where to start? has lope at low idle,runs fine otherwise

This is a classic intake plenum problem, see this thread, I posted a photo of the part that cracks from heat, dryness, etc

http://caddyinfo.ipbhost.com/index.php?showtopic=22307

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

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left bank lean/right bank lean,any suggestions where to start? has lope at low idle,runs fine otherwise

This is a classic intake plenum problem, see this thread, I posted a photo of the part that cracks from heat, dryness, etc

http://caddyinfo.ipbhost.com/index.php?showtopic=22307

Hello Everyone! I too am "NEW" here.

I have this same problem and found your post about this so I got a new Plenum and put it on tonight, No help though as there was no change.

My 2001 Deville Lopes, Surges harshly at stop & more so with Air on and I can not find any leak or unpluged line (Vacuum loss). I have no

PCV Valve as in the rear my pcv hose plugs straight into the rear cover and it does it after car warms up and even with air off. I thought it

too was a leak in the PLENUM but with a new one on now that's not it. Other wise the car runs great! 17 mpg around town higher on freeways.

I just got the car at the end of July and had the starter go bad replaced it but have this idle ordeal that's getting worst as time go's on. Any Idea's?

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Hello Everyone! I too am "NEW" here.

I have this same problem and found your post about this so I got a new Plenum and put it on tonight, No help though as there was no change.

My 2001 Deville Lopes, Surges harshly at stop & more so with Air on and I can not find any leak or unpluged line (Vacuum loss). I have no

PCV Valve as in the rear my pcv hose plugs straight into the rear cover and it does it after car warms up and even with air off. I thought it

too was a leak in the PLENUM but with a new one on now that's not it. Other wise the car runs great! 17 mpg around town higher on freeways.

I just got the car at the end of July and had the starter go bad replaced it but have this idle ordeal that's getting worst as time go's on. Any Idea's?

Pull your codes and post them here.

We will try to help.

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left bank lean/right bank lean,any suggestions where to start? has lope at low idle,runs fine otherwise

This is a classic intake plenum problem, see this thread, I posted a photo of the part that cracks from heat, dryness, etc

http://caddyinfo.ipbhost.com/index.php?showtopic=22307

Hello Everyone! I too am "NEW" here.

I have this same problem and found your post about this so I got a new Plenum and put it on tonight, No help though as there was no change.

My 2001 Deville Lopes, Surges harshly at stop & more so with Air on and I can not find any leak or unpluged line (Vacuum loss). I have no

PCV Valve as in the rear my pcv hose plugs straight into the rear cover and it does it after car warms up and even with air off. I thought it

too was a leak in the PLENUM but with a new one on now that's not it. Other wise the car runs great! 17 mpg around town higher on freeways.

I just got the car at the end of July and had the starter go bad replaced it but have this idle ordeal that's getting worst as time go's on. Any Idea's?

What did the old rubber plenum look like, was it cracked?

What do you mean you dont have a PCV Valve?

Check for codes, and post them here, you dont need a code checker, your Cadillac will provide you with the codes, go to the top of this page, click HOW TO, DTC CODES and follow the directions. An open EGR could cause this too, but check for codes

PS, who did the plenum job?

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

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Same problem with my car. I had a new intake plenum installed, as well as new intake seals, and new throttle seal. Also had the throttle cleaned. The seals may or may not have been necessary, but they were cheap and why not replace them why things were apart.

The car runs beautifully now!

Look at the pictures in the thread BodybyFisher posted and make sure you are checking the correct part!

2001 Deville, Sterling Silver exterior with Dark Gray leather, 93k miles

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left bank lean/right bank lean,any suggestions where to start? has lope at low idle,runs fine otherwise

This is a classic intake plenum problem, see this thread, I posted a photo of the part that cracks from heat, dryness, etc

http://caddyinfo.ipbhost.com/index.php?showtopic=22307

Hello Everyone! I too am "NEW" here.

I have this same problem and found your post about this so I got a new Plenum and put it on tonight, No help though as there was no change.

My 2001 Deville Lopes, Surges harshly at stop & more so with Air on and I can not find any leak or unpluged line (Vacuum loss). I have no

PCV Valve as in the rear my pcv hose plugs straight into the rear cover and it does it after car warms up and even with air off. I thought it

too was a leak in the PLENUM but with a new one on now that's not it. Other wise the car runs great! 17 mpg around town higher on freeways.

I just got the car at the end of July and had the starter go bad replaced it but have this idle ordeal that's getting worst as time go's on. Any Idea's?

What did the old rubber plenum look like, was it cracked?

What do you mean you dont have a PCV Valve?

Check for codes, and post them here, you dont need a code checker, your Cadillac will provide you with the codes, go to the top of this page, click HOW TO, DTC CODES and follow the directions. An open EGR could cause this too, but check for codes

PS, who did the plenum job?

Thanks for the reply's! I have a OBD II and the only code is a P0741 stuck clutch in trans and I know its common & ok to let go for now.

Old Plenum that was between the intake and throttle body looked fine but I could see the thin rib fade at the bottom so I replaced it in case.

I did the plugs with iridium ones & cleaned and checked everything to my limited ability and no change!

The PCV hose comes from the middle round of the intake and to the rear valve cover and plugs to a re stricter - A thinner looking then stock

PCV valve with a small hole and no spring or stuff inside (Empty) and it fits as if hammered inside the valve cover "Thight fitting" anyway but

its half as thick as the PCV valve I got to put there. The PCV valve gromit looks large to the hole that's there that would hold the valve its self.

The car acts as if it gasping for somthing and only when I stop at red lights and it take a second after stopping then when I press on the Gas

to go it struggles for a second and smooths out and runs perfect until I stop at the next light. Freeway driving is perfect and smooth - sounds

like a vacuum leak or bad PCV I don't have or ? maybe the digital EGR messed up. Its scary driving that way being it starts to really jump around

and very close to stalling at every stop! Thanks for any help!!!

Yes that is the right part on the Plenum, Big rubber hose between the intake & Throttle body needing 3 screws at one top and too bottom.

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Got to thinking (Should I fully pull out that re stricked thing where a PCV valve goes and rig in a way to put the OEM PCV valve back in?)

It lops from 650 rpm to 600 rmp to 625 rpm and so on at idle.

I did the job of replacing the Plenum. I show ok on everything on my obdII can reader but could have been cleared from dealer I got car from

at end of july and he is a small operation.

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What do you mean you dont have a PCV Valve?

BBF, the 2000+ engines don't have the rattle can PCV. They use a metered orifice.

I did the plugs with iridium ones

2000+ Northstars use A/C Delco dual platinum 41-987's. For some reason the Northstar seems to be rather fussy about the plugs. Maybe that's your problem.

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What do you mean you dont have a PCV Valve?

BBF, the 2000+ engines don't have the rattle can PCV. They use a metered orifice.

I did the plugs with iridium ones

2000+ Northstars use A/C Delco dual platinum 41-987's. For some reason the Northstar seems to be rather fussy about the plugs. Maybe that's your problem.

OH Thank you! I was lost about not having a PCV Valve and my book shows one and the Caddy dealer Parts guy was lost! My metered orifice is in

real bad shape, The outer male surface is scratched bad [Do you know where to get one?] Dealer was lost and only tryed to sell the Valve.

I had this probelm with the A/C Delco's before I changed them to Iridium's so that is not the cause but once this stubbling is fixed I will see if I have

problems from the Iridium's.

Thanks for your help! Still playing around with finding the issue,,,Could after fixing the Plenum and disconnecting the Battery the computer just

need time to reset and things will get better? My first drive I had the issue but maybe I need the computer to reset and the Plenum was fixed just

now its re setting its self???

New fuel filter also added...

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If your problem started with starter replacement and you have a vacuum leak that you believe is the PCV valve. Pull the hose off your PCV and see if you have vacuum, the starter is under the intake and the other end of the Pcv hose connects under the intake it may not be fully seated.

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I think I heard someone on the other board say that their 2000 still had a rattle can PCV valve so I could be wrong on the exact year of the change over. Make a visual check of yours to be sure.

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Got to thinking (Should I fully pull out that re stricked thing where a PCV valve goes and rig in a way to put the OEM PCV valve back in?)

It lops from 650 rpm to 600 rmp to 625 rpm and so on at idle.

I did the job of replacing the Plenum. I show ok on everything on my obdII can reader but could have been cleared from dealer I got car from

at end of july and he is a small operation.

I would not call ranging from 600, 625, 650 loping

Are your P0171 and P0174 codes gone?

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

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Got to thinking (Should I fully pull out that re stricked thing where a PCV valve goes and rig in a way to put the OEM PCV valve back in?)

It lops from 650 rpm to 600 rmp to 625 rpm and so on at idle.

I did the job of replacing the Plenum. I show ok on everything on my obdII can reader but could have been cleared from dealer I got car from

at end of july and he is a small operation.

I would not call ranging form 600, 625, 650 loping

Are your P0171 and P0174 codes gone?

That seem's to be what I see but at a red light the whole front end of the car jumps around harshly! up & down like its a bouncing ball - Smooth up till that point and again smooth once Im going. For the first time since I got the car the check engine soon light is on but I was gone all day so I will see what is there (codes) in the morning and post back!

Thanks

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Got to thinking (Should I fully pull out that re stricked thing where a PCV valve goes and rig in a way to put the OEM PCV valve back in?)

It lops from 650 rpm to 600 rmp to 625 rpm and so on at idle.

I did the job of replacing the Plenum. I show ok on everything on my obdII can reader but could have been cleared from dealer I got car from

at end of july and he is a small operation.

I would not call ranging from 600, 625, 650 loping update: 500 to 700

Are your P0171 and P0174 codes gone? I never had those codes.

Here is the code I am now getting. "PO410" secondary air injection system. Does that help anyone? is the (AIR) system bad or not connected good at the hose running down the back firewall? should I replace it? I found some more info on this and a service bulletin advising owners to update this system and the lines as water can get sucked up into the (AIR) system causing it to fail. My next step will be to check the fuse and listen for a vacuum sound at start up from cold start and see if I hear this sound. I did last night notice the headlights dim a bit and read that the (AIR) pump coming on can cause the lights to dim...Hope I am giving enough info for help.

Both front & rear PCV hoses are plugged in good and so are the thin ones from the (AIR) valve on rear valve cover ect. I never got this code until now but maybe I needed to replace the plenum first and was also leaking air there. Thanks...

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.

I would not call ranging from 600, 625, 650 loping update: 500 to 700

Are your P0171 and P0174 codes gone? I never had those codes.

Here is the code I am now getting. "PO410" secondary air injection system. Does that help anyone? is the (AIR) system bad or not connected good at the hose running down the back firewall? should I replace it? I found some more info on this and a service bulletin advising owners to update this system and the lines as water can get sucked up into the (AIR) system causing it to fail. My next step will be to check the fuse and listen for a vacuum sound at start up from cold start and see if I hear this sound. I did last night notice the headlights dim a bit and read that the (AIR) pump coming on can cause the lights to dim...Hope I am giving enough info for help.

Both front & rear PCV hoses are plugged in good and so are the thin ones from the (AIR) valve on rear valve cover ect. I never got this code until now but maybe I needed to replace the plenum first and was also leaking air there. Thanks...

UPDATE: As far as the P0410 code I found the hose coming from the front (AIR) pump cracked - replaced it and so far NO MORE IDLE issue on the first test run so hopefully its fixed! No other codes...

Thanks for your help on this issue!!!

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Glad to hear it, and that you figured out the P0410

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

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