[davemac2]

It could be something related to the fuel such as a marginal fuel pump/filter/or regulator. Do you have any trouble going up steep hills? You can check that by getting a fuel pressure gauge and attaching it to your fuel rail and taping it to the windshield so you can monitor the pressure while test drving it to see if the pump can maintain the pressure with high fuel flow.

It could also be other things such as a bad spot on your TPS, or MAP/MAF sensor. Is the engine a 4 cyl? Does it happen at only one particular speed/RPM range?

Could be related to a clogged air filter, bad plugs/wires, sticky throttle plate. Check you air filter first.

Does the engine revs increase when you floor it? Just wondering if your torque converter is functioning properly. Any problems with car stalling when coming to a stop? Does your throttle pressure cable going into the trans look in good condition? Shifts don't feel too soft?

dave mc