I have a 93 honda accord I have checked vacuum lines and all. I have replaced the iac vavle and fast idle thermo valve. Also habe replaced fuel regulator valve. But when the engine is cold it won't surge but when it warms up and I get up around 50 to 60 mph the engine kinda surges when I hit the gas pedal like it will speed up die off and speed up repeaditly. When I stay steady at like 55 or 60 it will sound like its reving high and then the pitch will change and it will run better. If it means anything in the summer when it gets extremly hot inside the car it won't start anthe tachometer bouncings and. Doesn't read right.
Please help been fighting this for a year now. Someone also said maybe a vehicle speed sensor.

 

Does the Check Engine light come on at all? My 91 accord would act like it was starving for fuel and would die when put into reverse and the cooling fans would spin backwards..Then the check engine light would come on and everything was fine.. Found it was bad brains [Ecu was dead] Try Replaing your Ecu with a junk yard unit and see if this helps with your problem..If it does then have fun..

 

I forgot to write that I have already replaced it and it still occurs it only does that when I on the highway at high speeds. It doesn't sound like its starving for fuel it just sounds like its running high pitched and struggling

 

I forgot to write that I have already replaced it and it still occurs it only does that when I on the highway at high speeds. It doesn't sound like its starving for fuel it just sounds like its running high pitched and struggling

 

Hmm.. weird.

 

I don't know if this helps or not...I have a 93 accord lx with a 2.2l motor in it, my car started doing some of the exact things your experiencing about a year ago..Come to find out the ignition control module (ICM) was at fault, what gave it away was the jumpy tach...They are fairly cheap and are a common problem.
Eric