Hello everyone, new here and in need of some assistance. I have a 95 Jetta 2.0 5 Speed with 99,000 on the clock. My check engine light has been on since I bought the car a few months ago. If I feather the accelerator it will pick up speed fine but if I jam it hard, she falls on her face. With the weather fluctuating here in NC its cold as winter one day and hot as summer the next. That being said, I've noticed something very unusual with the car. The check engine light ONLY comes on when its cold. When its hot or even above like 65* it goes off and the car runs like the dickens. Otherwise I have this acceleration issue. I've changed IAT, CTS, checked for vacuum leaks and I'm beginning to get stumped here. I can't check the light because when I jump the wires the light just turns off, no blinking codes. Am I correct in assuming that with an aftermarket stereo it must be disconnected in order to blink the codes? I would like to pin down the issue before throwing parts I don't need at it, and any help would be appreciated!