Speedo acting up!!!!!

[sageuvagony]

I am pissed here cuz my civic is acting gay! yesterday I was driving and my speedometer was jumping all over the place. Today the same was happening. It is very random when it does this. and on an auto tranny, when you're crusing in 4th gear, it'll lock into lower rpms. My moms camry does it, my explorer does it and my civic does it. but when the speedo is jumping around, the tranny revs higher and doesnt lock into 4th gear for those lower rpms.... Is my computer going bad or something? I know its the not guage itself because the whole car itself feels a lil funny when its jumping around (the speedo needle) and at times the car would bog a lil when taking off from a red light. Like I said though, it is very random. Could a ECU thats going bad be causing all of this? Weird speedo, bad gas milage for a near new engine....etc?

[Miataracer]

hmm... problem with the speed sender in the tranny? i dont know much about the autos but i am assuming it is computer controlled as opposed to being totally run by valve bodies and what not. maybe your torque converter wont lock up when the ecu thinks that your speed keeps changing