Throttle question

[rharlow]

I've got a strange symptom and looking for some possible causes. Car is a 94 Z34 Lum, 3.4L

 

Symptom is a slow response throttle - what I mean by this is that if in park, and I rev it up, it seems to take way too long for the rpm's to come back down to normal idle. The car seems to drive ok, although stepping on it, there is a slight delay/hesitation. It is not throwing any codes that I can tell - no Check Engine, but this car has the bastardized OBD 1.5, so I'm not having any luck pulling hidden codes. My first thought was a TPS, but wanted to run this by you guys. If you need more info, plese ask. Thanks for any thoughts on the cause!!

 

Chip

[Supreme Cutlass]

TPS is my thought, toohave you done a full tune up? Mine used to do that when I got it, a full tune up of filters, plugs, wires seemed to fix it.