90 Eldo 4.5 hi idle on deceleration

Well, got the care to pass emmisions.
Problem originaly___ bad hall effect and 4 injectors below resistance that was acceptable.
Then I failed emissions and checked the egr tubes at base of intake and they were plugged. Cleaned them out and nox went down from 1725 ppm to 350 ppm.

Only problem now is a fast idle on deceleration. TPS and ISC reset and all within specs, but idle stays high (1400 rpm) cruising at 25 - 30 mph. Have to use brakes and at 5 mph, it shifts down hard and idle settles down to 750 rpm .
Any one had this problem??
Where do I go from here??


thanks
Denny

sounds like a tranny problem

I had the same problem.
I checked the codes and it came up faulty TPS.
My mechanic said your TPS looks OK and I almost had to fight with him to change the low cost TPS.
I changed the TPS for $50.00 and the idle returned to normal.
If nobody can fix the problem I would advise going to http://www.gmpartsdirect.com and getting a new TPS. The base idle will need to be reset after installing a new throttle postion sensor.