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Hello,

I have a 1995 concours 4dr sedan. Just recently, I noticed that while stopped at the stop light, foot on the brake, that my car would seemed like it wanted to go forward while my foot was on the brake! Once I let off the brake and started forward, it was fine. My service engine light comes on after 2-3 minutes as well. My machanic friend said it was the gasoline that's causing it to do this and to purchase some intake cleaner and that will cure it. I did but it keeps doing it. What could be wrong? It has 94,500 mi.

Edited by foyosoul1
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Not sure if that car has one but most cars have IAC idle air control valves that control idle. That or throttle position sensor. Or for free its always good to clean out your MAF sensor and the butterfly of the throttle body with carb cleaner. That always fixes rough idles. Use a toothbrush and scrub the throttle body tube and butterfly good, hold it open and get what you can. To find out if those sensors are bad the best thing to do is get the codes as was said.

* 1966 Deville Convertible

* 2007 Escalade ESV Black on Black

* 1996 Fleetwood Brougham Black on Black V4P -Gone
* 1983 Coupe Deville Street/Show Lowrider -Gone

* 1970 Calais 4dr Hardtop GONE
* 2000 Deville DTS - Silver with Black Leather and SE grille GONE
* 1999 Seville STS - Pearl Red GONE

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What these guys sy it always works good,I couldn't believe how well my 94 STS performedafter cleaning the TB IAC and the EGR just try it you'll like it...

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If you have a 1995 then it has an ISC: Idle Speed Control motor instead of an IAC. It's pretty easy to take off and clean, and can very well be the cause of your car wanting to take off. Cleaning the throttle body plate and MAF sensors is a good suggestion as well, but DON'T use carb cleaner on the MAF. It WILL ruin it. If you would like a full description of how to take apart and clean the ISC motor, let me know and I can post it for you.

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If you have a 1995 then it has an ISC: Idle Speed Control motor instead of an IAC. It's pretty easy to take off and clean, and can very well be the cause of your car wanting to take off. Cleaning the throttle body plate and MAF sensors is a good suggestion as well, but DON'T use carb cleaner on the MAF. It WILL ruin it. If you would like a full description of how to take apart and clean the ISC motor, let me know and I can post it for you.

Where have you heard carb cleaner kills a MAF? Just curious. I have heard both ways. I have used it on a few and havent had any problems. I have been to lots of forums for other cars where they describe how to clean the MAF and suggest carb cleaner. I know some sensors are sensitive to things like o2's are sensitive to silicone and Ive heard others. Im just curious one way or the other and if you cant use carb cleaner what are you supposed to use?

* 1966 Deville Convertible

* 2007 Escalade ESV Black on Black

* 1996 Fleetwood Brougham Black on Black V4P -Gone
* 1983 Coupe Deville Street/Show Lowrider -Gone

* 1970 Calais 4dr Hardtop GONE
* 2000 Deville DTS - Silver with Black Leather and SE grille GONE
* 1999 Seville STS - Pearl Red GONE

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I've used carb cleaner (Gumout) on the TB (because I still have some), but it is a petroleum byproduct and does leave some residue. For the MAF sensor you'd be better off with an electrical parts cleaner or Brakleen which evaporate quickly and leave no residue.

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  • 1 year later...

I've used carb cleaner (Gumout) on the TB (because I still have some), but it is a petroleum byproduct and does leave some residue. For the MAF sensor you'd be better off with an electrical parts cleaner or Brakleen which evaporate quickly and leave no residue.

Thanks for your reply. My 1995 cadillac concours still idles alittle rough. While in park, I notice my cars vibrates. The steering wheel vibrates or shakes. When I'm at a light and take off, it goes slow. It sounds like it's missing. I replaced the spark plugs, air and fuel filters but still does same thing! It used to never do this. My accelaration would be smooth, quick and fast. What could be wrong? Thanks, wcrowe41@centurylink.com

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If you have a 1995 then it has an ISC: Idle Speed Control motor instead of an IAC. It's pretty easy to take off and clean, and can very well be the cause of your car wanting to take off. Cleaning the throttle body plate and MAF sensors is a good suggestion as well, but DON'T use carb cleaner on the MAF. It WILL ruin it. If you would like a full description of how to take apart and clean the ISC motor, let me know and I can post it for you.

Thanks for your reply. I noticed alot of talk about codes and so forth. I have no knowledge about codes and how to pull them up. Would be helpful on how to do that. Meanwhile, as I stated, my car is a 1995 cadillac concours. When I'm at a light with foot on brake, my steering wheel vibrates and the car shakes. When I move forward the car accelarates slow as the rpms rise fast. Slow accelaration, rough idle. What could be wrong?

Thanks, wcrowe41@centurylink.net

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  • 6 months later...

I see that this reply is a little late but maybe if someone else has this problem.

I had this exact problem before and it turned out that it was my spark plug wires.

I just bought a complete new set, popped them on and the problem never arose again.

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