Ok, my gf civic had some problems today. First was the engine began to rattle and CEL came on as she drove on the highway, it limited her to only 55mph and gradually decreased to 35 and so on. She pulled over and shut the car off and started it back up, CEL still on and car drives fine for a minute and starts to act up again.
I told her to pull over and check if there was any smoke coming from the rear end or from the hood and she couldn't not tell but she thinks she seen some smoke coming from the engine. I asked her if there was any other lights that come on the dash, she said no just only the CEL. Asked her to rev it in PARK and could only go up to 3000rpm.
The CEL is not flashing and none of the major warning lights has come on like the oil light and the temp light. The car has 100,XXX miles on it and has not had a tune up. I have changed the oil in the past 2 months. I dont know what it could be but this incident reminds me of the guy on street fire with his CTS-V that had some what the same prob as my GF.

Can anyone give me any suggestion to what could be going wrong.?
THANKs

 

ask her to make a video of it then post it up here so we can see