1999 Mercury Grand Marquis ls 4.6L (1) drove vehicle in a normal way, commuting from home to work daily. No speeding. In the mornings properly wait for 10 minutes to warm up the vehicle's engine prior to driving. Kept proper maintenance schedule by Ford/Mercury dealership. Never brought up to my attention of the possible default this part may cause down the line. Had a complete coolant flush for radiator. Replaced with new coolant. (2) misfire in cylinders 6 + 2. check engine light on. Small amounts of coolant leakage onto top part of engine, profusely around the spark plug chambers. Coolant come in contact with alternator affecting check battery light to go on. Vehicle showed signs of intense shaking at idle and at normal driving conditions within 1 hr after check engine light came on. Vehicle is a 199 Mercury Grand Marquis ls 4.6L. Vehicle could not be driven w/O being extremely shaky while driving. Hesitation present. On cold days, small presence of coolant traces were found inside the spark-plug pits along side the ignition coils and at times small vapor came from inside the engine noticed from inside the driver's seat coming from inside the hood causing concern. I found the following from the following Ford parts website: www.1aauto.com/1A/intakemanifolds/-/-/1aeim00012. "the original intake manifold, due to the design, has an abnormal tendency to crack, leading to overheating and in many cases complete engine failure and/or damage to other parts of the car's engine. This new and improved intake manifold is designed to eliminate those problems!". (3) dealership charged me over $1500 for replacing the intake manifold, spark plug and ignition coil for cylinder #2 plus an oil change and filter. I requested old parts back and only the spark-plug and ignition coil was returned to me.

- Chicago, IL, USA