Engine Performance problem
1997 Ford Taurus 6 cyl Front Wheel Drive Automatic 153000 miles
At 148000 the car developed a minor misfire on starting. At highway speeds, a mis fire sometimes occured and when the torque converter locked up, the engine stumbled. Pulled all plugs that have about 25,000 miles on them, they are like new. Replaced sparkplug wires and there was small improvement. Scanned OBD-II codes. Nothing set or pending. The mis fire and rough engine performance is very gradually getting worse but still no codes are present. Fuel economy is not effected, and if anything may have improved slightly. Driving at a steady speed of 40-50 mph, it runs fine, give it the gas at these speeds and it stumbles, runs rough, etc. Recently I hooked the computer up and measured sensor outputs. The only thing I noticed to me that was odd was reving the engine in park to 4000 rpm, the short term fuel trim increased from near zero/+/-3% to +40% and the engine would not go over 4,000 rpm. Still has a misfire on cold start that goes away in a minute or two and still has no codes set or pending.
have the same problem?
Monday, May 11th, 2009 AT 9:52 AM