Transmisson Issue

I bought a 1995 dodge intrepid with a 3.3 liter engine it and iam starting to have trouble with the transmisson i think. When i take off in it when i get around 40mph it seems to start jurking a little bit and the tach and speodmeter jumps a up and down. But if i take off and the gear changes around 45mph it doesnt have any problems and it changes smooth do anything have any problems simlar. Does anybody no what the problem is or how to fix it.

Have you done the key dance for codes?? Turn ignition key on/off, on/off, on with out starting engine and within 5 seconds and the check engine light will blink giving you any codes present. Example one flash pause flash flash means code 12.

Does engine miss? Have you changed the tranny filter and fluid recently. Make sure ATF+4 fluid is only used, DO NOT use a universal fluid with additive as this will damage tranny. Check the input and output sensors and their wires and conncetions.

Post any codes and we hopefully we can help more to diagnose.

no codes i did change spark plugs and wires but it was doing that before i replace those parts i cant figure out what it is but one thing i did notice is it does it around 40mph when the gear changes I kind of notice this morning its starting to do it around 60mph.i put 400 miles on the car yesterday with no problems i just dont have any clue what the problem is.