Surging while driving

i was driving to home from work this morning and just cruisin as one does after a long day of work just cruisin down the street when i downshift to second gear to make a turn just after my works parking lot and as i get going at about 3krpm or so (cant really tell as my tachs not working) so around 3 or 4000 rpm the motor would surge if it wasnt under about 70% load or open throttle then again in 3rd and slightly in 4th cant really tell in first as i have a 4cyl tranny and that gear is gone before i notice anything. so what do you guys think this surge could be i just changed my plugs and wires my map sensors vacuum line as it is pretty much wasted as to my theory about that but still no improvement i had to raise my idle to keep the car from surging to death while at stops and its not a good thing to be sitting at a light then having a cop pull next to you and you cant lower your rpms and your car sputters like its getting kicked in the balls to get going. so any info or thoughts would be VERY helpful
Thanks
Daniel

no i changed everything in hopes to find the surge problem i always set my TPS sensor when i change anything with the throttle butterfly position as whether or not my tps ITSELF is bad i dont know but what else comes to mind as to why this happens
ive changed so far my air filter my spark plugs, wires, cap and rotor, and coil, and today i ran some injector cleaner in there too and it slightly fixed it today but its running like theres less power im doing an oil change tommorow and then i guess im gonna put my shocks on too but i really wanted to get this solved tommorow so my timing and all other parts associated with the ignition are getting checked tommorow as i need to fix my tach also
so any info would greatly be appreciated fellas

i found out what happened... well my passenger side muffler had been ding up a bit and started to fall off... so the backpressure i guess what f***ing it all up, cuz when i tore off the muffle and put a cheapo on there to fix it the car drives like a dream... just like the day i bought it... thanks anyway