2003 ford explorer xlt rough idle i changed spark plugs no engine light

The lack of a light is confusing. I have a 2003 explorer with a v-6. Rough tranny, but had the idiot light. Upon instructions from my tranny guy I had to leave it running and go to the shop. Read the code and replaced some electrical connection on the transmission and it was ok. I would suggest checking for error codes. The light on the dash may be defective.

I'm going to suggest the same thing. Check engine lights can be removed. See if the check engine light (lower right hand corner of your cluster) illuminates and goes out during start cycle. If it's running that bad it has to have some kind of code in it. If your ses light doesnt cycle it's either removed/broken or your pcm has a problem. Is your speedometer/tach reading correctly? Your transmission uses several readings to decide when it shifts. It's not a "R", Salvage, flood, or reconstructed title? This in my eyes and from what ive seen in the past has wiring issue written all over it... Hope this helps. -Mike Nissan asst service manager/explorer owner/fan

Thanks guys, this information was very helpful