2001 GMC Safari Idle

Bare with me, I do not know anything about cars and am at the mercy of mechanics - my story,
vehicle broke down on highway - I heard a big clunk in the middle of the van and then it seemed like no gas to vehicle - had power but it died, had it towed to mechanics and
had the fuel pump replaced on my 2001 GMC Safari $550,
after I picked up the vehicle that day it was idling high, I basically sit and steer and do not need to touch the gas pedal the vehicle builds speed upto 50/60 kilometers/hour.

The vehicle had a recall so I brought it to the the GM dealer for the recall work two days after fuel pump was installed and asked them to look at the idle while they were doing the recall - they asked if work had been done recently as the there was a problem with the throttle screw
order notes states:
Scan Data - output test 1AC idle spped, IAC O.K., DATA IAC Counts 0 TPS VOLTS .78, High, throttle stop screw adjusted too high, screw is seized, will not adjust. dealer advised screw would definately break it he tried to adjust and I would be looking at more $$$ and to bring it back to mechanic.

so I brought back to mechanic the next day and asked he correct work he had done and not to do any other work...he called later that day and advised dealer wrong, it was a sensor and not throttle stop screw as they are not adjustable and come from the factory like that -they are not adjustable
he has given me a new bill $266. $170 labour $62 parts
his computer scan indicates idle too high, coolant temp sensor registere -40 degrees F when engine at 190 degrees F operating temp.
replace defective coolant temp sensor & replace broken cracked vacuum line


picked up vehicle and drove it a mile - still doing the same thing

any one have any thoughts? sorry for the length but I didn;t want to leave anything out. I don't feel I know enough about cars to argue with mechanic but the vehicle did not do this before fuel pump installed
he denies that his work has anything to do with this

any help would be greatly appreciated


thanks
Sandi

upon first picking up your vehicle, you should always take it around
the block & make sure everything is working properly before just
leaving. this way you can ask things like, "why is it idling high,
if you replaced the fuel pump (which is located in the fuel tank).
the two things shouldn't be related, but - in trying to diagnose the
initial problem, perhaps mechanic #1 was "investigating" something at
the throttle body & adjusted something incorrectly as an attempt
to see if making such an adjustment would affect a cure. if the
thing will drive to 50mph without touching the gas, then it sounds
like the throttle is open as though the screw was at the max limit.
ask them to actually show you the screw in question. if this screw
is somehow teetering on the edge of breaking off, why can't they
simply drill it out & either ez-out the remainder, or chase the
threads with a tap & install a new screw? i would also check the
throttle cable adjustments - if it's too tight, it'll hold the
throttle open like that - since it's impossible to know what mechanic
#1 did, & you couldn't ask him why it was running so fast at the
beginning, it's tough to say without actually looking at it, but i'd
ask them to show you the screw first, & see why it is that it
couldn't be drilled out & replaced.