Throttle positioning sensor nightmare

[Zan Stout]

We have replaced the TPS on a 1993 Olds ninety eight and the ECM is still coding a 21 (TPS circuit signal voltage high). We have checked all the wires leading to and from the TPS to the ECM and the CEL is still coming on after a minute or so the rough idle begins. Please Help!

Thanks,
Zan

[DrJay]

You should have a feed line with 5v and a return line with 0.3-.7v at idle. Be sure of these specs and it may tell you the direction of the problem.