My check engine light came on last night while pulling my horse trailer, now it will not go but 25 MPH with the trailer, without the trailer it seems to run fine, any ideas?

 

Take it to an Auto-Zone or Advance Auto Parts store they will check your computer for free. That is funny though. It almost sounds like your tranny dosen't like it. If I remeber right some of these trannys have a "limp home mode" that will keep them in 1st or 2nd gear. It may be something like that. Good luck.

 

Thanks. ends up it was the injectors, got them replaced under warranty and everything seems to be fine now.

 

Is it a turbo if not then that sounds right

 

They are turbo-charged.