: 2000 Deville Mechanical Issues *HELP*

08-14-08, 02:25 AM
I own a 2000 Cadillac Deville, Purchased a year and a half ago, just recently passed 70,000 miles. I'm having a rough time with the engine feeling like it's going to stall. I was in the drive thru and turning the wheel, or just sitting and waiting for $.59 cent cheeseburgers :cool2:, the engine starts to sound like it's goin to stall, the car vibrates and when you press on the gas, it kinda sputters like there's not enough gas getting to the engine. I use premium gas, like it's called for.

I recently pulled the codes and have codes.

ABS C1295 - BRake Lamp Switch Circuit Open

DIM P1540 - A/C Refrigerant Over-Pressurized

PCM P0171 & P0174 - Fuel Bank 1 & 2 Fuel Trim System Lean

Could this need a new fuel pump? I'm at a loss, I tried doing some research and all I got what a possible vacuum hose leak. Please help.

I'm currently going to the police academy, and definitely need my car. :nono:

08-14-08, 08:55 AM
Go through the Seville, Deville, and Northstar Performance threads and look for questions on vacuum leaks, plenum leaks, and overpressure valve leaks.

Go to Walgreen and buy a cheap stethoscope and remove the chest diaphragm, replacing it with a piece of vacuum hose (Western Auto, Pep Boys, Auto Zone, etc.) and listen around the intake manifold flange, the underside of the rubber plenum which connects the throttlebody to the intake manifold, and the front, or drive belt end, of the manifold. A vacuum leak (your PCM codes point to one) will sound like a high pitched hissssss.

Did you add a can of R134a to your a/c system ? High pressure code........

08-14-08, 12:41 PM
Sub is right - look at the plenum leak. Also consider the crankshaft sensors - they are a common cause of stalling, although you don't have any codes for that

08-14-08, 02:06 PM
sub, I haven't added any refrigerant to the A/C, so I'm not sure what that codes about. But I appreciate the other info. Sounds like a common problem, I wish I could better explain what it's doing. I really don't wanna bring it to a shop if I can figure out what it's gonna cost me.

08-14-08, 04:46 PM

I took it to repair shop that has known my family for about 15-20 years. While he said he couldn't help me out on the labor costs, the total cost would be $598.60.

Invoice As Listed-

1. Fuel Emissions Service
Parts - $49.95 Labor - $40.00 Total - $89.95

2. Throttle Body Gasket
Parts - $53.56 Labor $67.86 Total - $121.42

3. Plenum Gasket SET(Said they are 8 rings)
Parts $73.80 Labor - $247.58 Total - $321.38

But he did confirm that the plenum gasket was the problem and said with the amount of gas I will lose, I should consider getting it fixed soon. Didn't charge me anything for a diagnosis. And said the Fuel Emissions service wasn't mandatory, but would be good to have because of the carbon build up.

Is this something easy enough I could do myself?

08-14-08, 05:08 PM
Seems like it would be either #2 or #3, not both - most likely #3. All pretty easy stuff to do yourself if you are handy. Labor on #2 sounds about right, but labor on #3 seems high to me - couldn't take more than 1 1/2 hours, could it sub?

08-14-08, 07:51 PM
Your family friend is taking you to the cleaners.

There is only one plenum associated with the intake. It costs $30 at the dealership

There are eight intake manifold gaskets, they are $15 at autozone and come as a set.

You can have all of this replaced in a couple of hours.


08-14-08, 08:18 PM
C and tat, thanks for your input, really does sound like he's taking me to the cleaners I guess. I didn't have any idea the plenum was an actual tube I thought it was, well a gasket. Should I go ahead and change the intake manifold gaskets? and Should I waste my time with the Throttle Body gasket?

I sound stupid I know. Just a beginner at this. :-(

08-15-08, 10:11 AM
Not sure why the throttlebody gasket would need replacement; if it did, it would be the first one in this forum. You need to remove the fuel rail and injectors as a unit in order to pull the intake manifold, which must be done to change the offending plenum, the rubber boot between the intake and throttlebody. Not a tough or complicated job.....as others have said, worst case 3 hours, which would include making everything squeaky clean again.

The rubber plenum is a dealer item, and the intake gaskets and maybe O-rings for the injectors can be had from a NAPA or other large parts house. Best bet for everything in one box would be to call Luke in Parts at Lindsay Cadillac, -----------> over there, M-F, 9-5 EDT. They sell online and ship everywhere. Meanwhile snoop through your car parts at www.rockauto.com (http://www.rockauto.com). Most parts have pricing and pictures (click on the small part icon).

Spend the $$$ for a real factory manual from www.helminc.com , or subscribe your car to www.alldatadiy.com .