Could well be the tps, they tend to suffer a bad spot just off idle, right where you need it for trickling through traffic, you could turn the sensor so it is "higher" at rest than this point, but it will overfuel slightly all the time then, ideally of course you need a new tps.
They are 0.55 Kohm, so you will not have a problem finding a "universal" sensor of this value as most are around then 0.50 Kohm mark, the shaft is the regular 8mm "D" shaped connector commonly used.
You will get a new connector to use on the loom, as the universal type ones are generally a round 3 pin afair, so a bit of easy wiring is needed, pm if unsure of connection details.
This is what I put on mine £20 brand new when I took the duff one of I simply drilled and tapped the two areas marked on the flange under the old sensor with a small circle as they were bang on where I needed to drill and tap for screws to secure the new sensor, this also ensures a excellent supply of easy to get inexpensive tps's in the future.
I can't of course gaurantee it is the problem, might be better to get it to set up place so they can see CO etc esp at around idle, might just be slightly lean, need the fp upping slightly etc.
tabetha