2001 SL1 with High Idle
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Joined: Dec 2014
Posts: 2
From: Oak Park, IL.
2001 SL1 with High Idle
I am new to this forum (just signed up). I bought a 2001 SL1 with 75,000 miles on it; it is in great shape as well.
I noticed that when I drive more than 25 minutes it has a high idle, 2500-3000rpm (not happening even when I drive to work about 13 miles, but mainly longer drives).
I had my dealership (where I bought it and they are helping me by getting parts at cost, with no labor charge) and it came up with P0507 (SES light came on recently, like last night). I notice that the rpm fluctuates a little, especially when braking; and was told by a couple mechanics (one who was told by a friend who works for GM) that based on what he described to the friend that there is a leak and possible Throttle position sensor could be bad.
I knew buying a 13 year old car that I'll have to put some money into it, but don't want to do any unnecessary changes.
I have thought I should start by replacing the intake manifold gasket (with a felpro as people say it seals better that the oem one); possibly the TPS as well.
Any help is greatly appreciated.
I noticed that when I drive more than 25 minutes it has a high idle, 2500-3000rpm (not happening even when I drive to work about 13 miles, but mainly longer drives).
I had my dealership (where I bought it and they are helping me by getting parts at cost, with no labor charge) and it came up with P0507 (SES light came on recently, like last night). I notice that the rpm fluctuates a little, especially when braking; and was told by a couple mechanics (one who was told by a friend who works for GM) that based on what he described to the friend that there is a leak and possible Throttle position sensor could be bad.
I knew buying a 13 year old car that I'll have to put some money into it, but don't want to do any unnecessary changes.
I have thought I should start by replacing the intake manifold gasket (with a felpro as people say it seals better that the oem one); possibly the TPS as well.
Any help is greatly appreciated.
Senior Member
Joined: Mar 2014
Posts: 1,363
From: Louisiana
I would start with cleaning the throttle body, changing the plugs, and the wires. Then from there change the IM gasket.
And welcome to the forum.
Might want to make a signature (top right side, by your username, click user cp) with your name and car before the moderators get to you. Just a heads up.
And welcome to the forum.
Might want to make a signature (top right side, by your username, click user cp) with your name and car before the moderators get to you. Just a heads up.
Senior Member
Joined: Jul 2011
Posts: 5,557
From: Anniston, AL
Have one of those "mechanics" test the check valve on the power brake booster. It sounds to me like a vacuum leak there, but I'm not a mechanic. Hell, I don't even know if your car has a check valve on the brake booster.
Super Moderator
Joined: Jul 2005
Posts: 12,387
From: Slightly off center
Personally I'd start with a full throttle body cleaning, IAC cleaning, and spraying carb cleaner or such all around the vac hoses (incl brake booster line), intake manifold, and throttle body.
Do you know if the car had any major service done to it before you took possession of it? (Not clear to me how long you've owned the car)
Also, please mouse over your name in the top right corner of the screen, select user CP, and then edit signature on left to create a signature with name, location, and what you drive. Thanks.
Do you know if the car had any major service done to it before you took possession of it? (Not clear to me how long you've owned the car)
Also, please mouse over your name in the top right corner of the screen, select user CP, and then edit signature on left to create a signature with name, location, and what you drive. Thanks.
Senior Member
Joined: Dec 2005
Posts: 435
From: United States
A 2000 to 2002 SL or SL1 with a P0507 code, the immediate suspect is the intake manifold gasket. Its easy to check by spraying something around the #1 port at the upper outboard corner. This is where the OEM gasket gets sucked in most often as there is no fastener on this corner.
Spraying something like carb cleaner or WD40 will have some affect on the idle if it is leaking there as it will be sucked into the intake. I'm pretty sure the mechanics will confirm the leak, but always test before replacing parts, test=not much $$, random replacing of parts = lots of wasted $$$.
If it is confirmed, use a felpro gasket and not an OEM. The OEM gaskets do not have enough support. The felpro is steel backed and will be less likely to get sucked in.
Edit: the felpro can be hard to find. If you have to use an OEM, use Copper Kote on the head side of the gasket. One little tip for the mechanic, rock the engine to the front of the car and tie it in place. A cargo strap works good for this. This will give more room to access the manifold nuts and get them off. GM went a little overboard on the stud length. I believe that GM has difficulty enhancement engineers whose job is to make things harder for the mechanics.
Spraying something like carb cleaner or WD40 will have some affect on the idle if it is leaking there as it will be sucked into the intake. I'm pretty sure the mechanics will confirm the leak, but always test before replacing parts, test=not much $$, random replacing of parts = lots of wasted $$$.
If it is confirmed, use a felpro gasket and not an OEM. The OEM gaskets do not have enough support. The felpro is steel backed and will be less likely to get sucked in.
Edit: the felpro can be hard to find. If you have to use an OEM, use Copper Kote on the head side of the gasket. One little tip for the mechanic, rock the engine to the front of the car and tie it in place. A cargo strap works good for this. This will give more room to access the manifold nuts and get them off. GM went a little overboard on the stud length. I believe that GM has difficulty enhancement engineers whose job is to make things harder for the mechanics.
Last edited by keith; Dec 31, 2014 at 12:05 PM.
Senior Member
Joined: Mar 2014
Posts: 1,363
From: Louisiana
Greatest thing I've heard in a while.
Senior Member
Joined: Mar 2006
Posts: 3,278
From: Arizona
Sounds like the beginning of the SOHC intake leak.
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Top right of most pages you'll see your username. Next to it a drop down, click it. Add your first name, location, and car to your "signature". Stop in the new member sub-forum and introduce yourself to the gang.
Once you reach 25 posts send a jpeg (photo) to me and I'll set you up with an avatar. If you do not reach the minimum 10 posts your account will be shut down as inactive.
send to
sw2cam@yahoo.com
Subject line "AVATAR"
include your "username"
Last edited by sw2cam; Dec 31, 2014 at 03:51 PM.
