I have a 1995 Ford Contour SE with less than 40,000 miles on it. Every once in a while the check engine light comes on for maybe 10 seconds then goes off again, then in a couple of minutes comes back on again, then off again, and so on. This seems to only happen when I’m driving over 55 mph. The shop says there are no codes when they check the computer. Any ideas??? Friends have advised me to ignore it but it stresses me out every time it comes on! Thanks! (PS - I recently had a tune up and it’s still happening.)
The shop didn’t take it out, with scan tool attached, and drive it over 55mph? Ask them if they would attach the scan tool and let YOU drive the car until the light comes on, and you can read the code.
When that happens, I change the oil pressure sensor.
Hopefully they checked the codes correctly. There are actually 3 steps.
The first is the KOEO (key on, engine off) in which codes are given, followed by a separator code, which is then followed by what is called the Continuous Monitor, or wiggle test.
The third is the KOER (key on, engine running) in which the RPMS are elevated and codes are given. Depending on how the test is performed a few codes such as 77, 83, etc. may be given. These have to do with the brake pedal, power steering, etc. and can be ignored.
Any code 11s mean a pass.
You might verify they checked the codes this way or even get someone like AutoZone or Advance Auto to check them. They will do this for you free. Post any results back here for further discussion and I would not ignore it.