My 2006 Jeep Liberty CRD just stopped running while driving. I had it towed to a garage and they found stink bugs in the air filter so they cleaned everything out. Now they are telling me that the electronic throttle valve needs to be replaced. I'm really at their mercy here, can you tell me if that sounds correct?

You might be carrying a ghost all along

runs hot, so how much, use a meter?
full flush the coolant system yet.
test the Radiator tube for clogging, using any cheap, IR pyro temp gun? made, (ask how)
clean the leaves, and bugs out to all cores in front of car.
A/C condenser and RAD yet?
are fans working at RAD?

What color is the smoke?
White,blue or grey?
Please post the color of smoke on reply.

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Use a bottle of yellow HEET dry gas to remove any moisture problem in the fuel.

Clean / replace air filter.

Top off ATF to MAX level.

Use starting fluid to aid starting.

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what engines, many used world wide
can fix , engines , until that . is known.
gas or diesel? size, cylinder count.

The 2006 Liberty does not have one. You can add one if you want though... On the Jeep forum Jeep Jeepster said: "Correct, the liberty doesnt have one. I added a filter media to help filter out dust":

http://www.jeepkj.com/forum/showthre...ghlight=filter

With the quality of oils available today I would think that 6,000 Miles is an appropriate interval for normal use. If you are doing towing etc a shorter interval would not hurt it. There is nothing like good clean oil and filter change to prolong the life of an engine.

fuel pump relay . you should hear the fuel pump run for 5 seconds as soon as you turn the key on .after that the cranking sensor takes over when engine it turned over to start

Most common causes of that kind of problem are the fuel pump and the crank sensor. Crank sensor should set a code, pump won't. Less frequent but worth mentioning is the ignition switch. Do some testing using a haynes or chilton manual as a guide,. All you need for that is a digital multi-meter.
Before testing anything, check that all the ground points under the hood are clean and secure. there are more than just the battery to the block...check all the smaller ones as well.

use dextron 6 transmission fluid -- recommend using fram transmission filter kit

there is also a lift pump in the fuel tank with a one way valve, sounds like u r loosing ur fuel pressure somewhere in the system i would check there first and work my way towards the engine