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Auto Doctor: Subaru cars long plagued by heat shields

Heat shields have always been a problem in

Heat shields have always been a problem in Subaru vehicles, including the 2010 Forester. Credit: Subaru

Dear Doctor: I'm the original owner of a six-cylinder 2004 Malibu Maxx with just over 100,000 miles. For several years there has been an intermittent problem starting the car right after it has been driven and then shut off. It turns over, but doesn't restart. Waiting a while or holding the gas pedal to the floor helps. Trouble codes do not show on a scanner. Any thoughts? -- Donald

Dear Donald: There needs to be a computer check during the time of the no-start condition. Fuel pressure also needs to be checked. Crank shaft position sensors are a common fault with this condition. The technician will be able to check all sensor and computer inputs to see exactly what is missing and causing the no-start condition.

Dear Doctor: I own a 2005 Lexus GX 470 with 85,000 miles. It has been great, but about once every other month it stalls when I'm at a light or hit a big bump. It re-starts right away. Any suggestions? -- David

Dear David: There are many possibilities that can cause intermittent stalling at a stop and with your foot off the gas pedal. A dirty throttle body is the most common fault without setting a check engine light.

Dear Doctor: I have a 2003 Toyota Avalon. When I step on the brake the engine races and the car lurches forward. I have to apply both feet on the brake and even then it is extremely difficult to stop the car. This has happened about 10 times in the last 10 years, but this year alone it has happened four times. The mechanic said without duplicating the problem he could not be sure of its cause, but cleaned and lubricated some plate. The car has only 65,000 miles and the only other problem is that when the undercarriage gets wet from the weather, the A/C goes off and it switches to outside air. Help! -- Christine

Dear Christine: There's no connection between the brake pedal and gas pedal, so it's unusual for the engine to race when the brake is applied. I checked for any Technical Service Bulletins or history in our database and found none. I suggest you check to see if a possible floor mat, if equipped, is moveable. If so, remove it. As for the A/C that stops working when you go through a puddle, I suggest you take the car to a shop that can duplicate this issue to determine how to fix. They will use a water hose and spray the area under the car to duplicate the condition.

Dear Doctor: I had my dealer check a rattling noise on my 2010 Subaru Forester. The service manager told me the SUV was running fine, having just had its 60,000-mile service. He explained the noise was coming from loose heat shields and nothing more and that the vehicle performance was not an issue. Quieting the noise would involve replacing the heat shields at a cost of approximately $800. My concern is trading or selling the vehicle with this noise. Is there a less expensive remedy? -- Paul

Dear Paul: Heat shields have always been a problem in Subaru vehicles. Heat shields are thin metal pieces that are bolted together around the exhaust, especially the mid and front section of the exhaust. They serve two purposes. First, to keep the exhaust system heat contained to ensure catalytic converter efficiency. The $800 is expensive. We also see this often and are able to install either a hose clamp or muffler clamp around the shields involved. When we have other vehicles with rotted heat shields around the catalytic converter we use a big strap clamp available at the local home improvement store. This service holds true for any vehicle with this problem.

Dear Doctor: I have a 2000 Ford Taurus. Is there a way I can siphon gas out of it in an emergency to use in my generator? -- Tony

Dear Tony: There is no way to simply to put a hose down the fuel filler and suck out the gas. Today's vehicles have multiple safety features, including an anti-siphon valve between the gas fill and gas tank. -- Junior Damato

Junior Damato is an ASE-certified Master Technician. Email questions to Mail questions to: Motor Matters, PO Box 3305, Wilmington, DE 19804

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