Engine Mechanical problem
1997 Mercury Tracer 4 cyl Front Wheel Drive Automatic 89000 miles

Ok this is scaring me to death, If i have to sit at a light my vehicle ither hard shifts or theres a major hesation before it shifts into first, a year ago i had the trany rebuilt, and just had a tuneup to no help, and when it hards shift the check engine light flashes then turn off. I had it happen just the other day so i took it over to a shop to see if it showed any errors there were none???? ie not turning off the engine...