My blazers check engine light came on and went off for a couple days. Now its on goes off sometimes but, the prob. is that it feels like iam pulling a trailer and wont shift into overdrive. Maybe a vaccum line or ect? Dose anyone have an answer.

 

The first order of business is to get the codes read. Even though the CEL has gone out, the previously set codes that caused the CEL to illuminate in the first place will be stored. Let us know what the specific codes are (Pxxxx, Cxxxx, Bxxxx, or Uxxxx where 'x's are the numbers).

 

It came up with code p0753 shift solenoid. I have done filter changes on older rigs could i do this my self?

 

P0753 - Shift Solenoid A Electrical

That will run you through the diagnostic steps. This code does not entirely mean that the shift solenoid is bad. It could be a damaged wiring harness inside the transmission or damage outside the transmission.