Mercury Grand Marquis owners have reported 4 problems related to catalytic convertor (under the engine and engine cooling category). The most recently reported issues are listed below. Also please check out the statistics and reliability analysis of Mercury Grand Marquis based on all problems reported for the Grand Marquis.
While driving the brake lines failed and had to be replaced. The owner came outside and saw the brake fluid on the ground and realized that the brake lines failed. The owner drove the vehicle with no brakes to the dealership and they repaired it. Then the owner realized that the brake lines were rusted. The left rear seat belt was replaced twice. The wiper motor, wiper switch, drivers side mirror switch and rotors were all replaced. The turn signal switch, driver window switch , tail light , catalytic converter were replaced. The consumer was told the ball joints and shocks were bad. The battery was replaced.
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all problems of the 1996 Mercury Grand Marquis
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While driving mil code p0420 set. Ford TSB 03-24-5 indicates pcm reprogramming rather than replacement of catalytic converters required. Despite being within emissions warranty coverage period dealer charged $119 for this work, claiming emissions warranty did not cover this work. Defective programming of pcm to cause the check engine light to come on, requiring a visit to dealer. Can't pass emissions test with light on, should be against the law. In any case the reprogramming of the pcm should have resulted in no charge. This failure resulted in a mandated, due to state emissions testing, visit to dealer and a charge for service to fix a manufacturing defect. The pcm was reprogrammed, according to dealer, and currently light is off. It is very easy to program the pcm to send erroneous codes at any time, especially when out of warranty, allowing the car dealers to create a cash flow they might not otherwise have. This should be illegal!.
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all problems of the 1997 Mercury Grand Marquis
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Two catalytic convertors have burned out while consumer was driving vehicle. Has not contacted dealer.
While driving engine light came on and remained on. Could hear a knocking noise coming from under the hood. Had taken vehicle to dealership, and mechanic indicated it was the catalytic converter, but the problem had not been repaired.