83 500 SEC Hi Idle Help Troubleshoot

[CamelotShadow]

Car has sat used only 300 miles in 4 years.

I've drove it about 60 miles back and forth to the shop trying to fix a engine that heated to 120 & once to red.

Thermo was determined to stick so was changed

Then it still ran up to 120

Temp sendier was switched
Still 120

Then new radiator
thats brough temp to 95/100 range...

So now no danger there

Car starts up right away cold or warm
Car has trouble starting hot
lots of cranking & had to use accelerator
which manual mentions so it might not be so odd.

Problem
When started idle runs 1500
stays high til about 80 C
then comes down to 1000 maybe 800

Drives in 650 range so thats OK.
Does have some slight lumpiness at lights when stopped in drive

If its idle on start could it be wam up regulator
There is a vac hose taped
I am going to change the 3 vac hoses to the warm up regular
Stupid ? are the hoses hooked up to the warm up reg air & not fuel?

Other strange thing is the water temp guage still quivers as it has from day 1 which is why I suspected possible guage problem but mechanic was said he found cool spots in center of radiator
I sae him using a onfared gun so I am assuming the temp guage is reading ok. Still don't know why at times the neede does a quick waiver & temp changes say 5 degrees in matter of seconds????

I have been reading OVR problems can have all sorts of compiication when they are failing.

I have also read to change vacumn hoses
I am trying to locate & find replacements for all I can access

I am no mechanic. so I am trying to understand the possible causes to point the repair in the right direction.

Mt mechanic drove the car & apparently it drives well enough for him & never made mention of the high idle start or slight lummpiness at lights.

I know the car has sat & as he says needs to be drivem
but I am concerned to drive it before I know its not in any danger to the car or myself...

Was just reading early O2 sensors did not fiunction properly til exhaust was in 500C range so they are really not in affect at start up while it doesn't rule it out it would seem if when its warm the idle comes down that the O2 sesor is OK or at least not causing initial problem?


Thanks for any comments...