Your success with solving the high idle complaint will come easier with a good plan of attack. The first thing to determine is whether the high idle is caused by a mechanical issue, such as a faulty IAC, or a throttle plate that is not closing, or if the idle speed is actually being commanded high by the computer. One of the easiest ways to do that is to simply unplug the IAC with the truck at idle, and allow the engine to slow to the "minimum air rate" or base idle speed. There is no published spec, but if your minimum idle speed is in the 500-600rpm range in park, thats close enough. There is no normal service adjustments required, but if something is keeping the throttle plate from closing, then you'll have to correct that. Most likely, when you unplug the IAC, you will find either a normal minimum idle, or no change at all. If there is no change, and the throttle is not sticking open, suspect air is getting around the throttle plate, which could be a bad IAC, because thats exactly what it does, it allows air to enter the engine around the throttle plate. Normally the computer has complete control of the IAC, but it can fail mechanically, so it must be checked. The last senario has the idle speed being correct when the IAC is unplugged, and then going back up when it's plugged back in. this would suggest the computer is actually commanding the idle speed high. The questions from here are, is the computer getting a high power steering pressure input? Is the TPS spiking low, causing the computer to think the engine is at part throttle? Is the ECT, or IAT reporting to low of an engine temperature? This is where the correct scan tool becomes so important, because it allows the person trying to fix the car to see this information right from the computer.

Disc brake noise isn't unusual. Some pads are more prone to it. There is a product (high temp grease) they sell at NAPA that you put between the piston and pad. Permatex has a product you spray on the back of the pads. I wouldn't guarantee either of those to do much. What's always worked for me is having the rotors and drums machined. Cutting the glaze off of them always worked for me. FWIW my son's Ford PU was squeeking bad. It had a bad axle seal and the pads and shoes were getting low. Fixed all that last weekend for him except he didn't want to spring for the $60 to have the drums and rotors machined. They were quiet last week when I was done with it, but he says they're starting to make noise again. Told him that might happen without the machine work. Odds are the gas guage inaccuracy is due to the sending unit in the tank. Unfortunately, I believe it's combined with the fuel pump. I'd bet it's an expensive part, and the tank has to be removed to install. I wouldn't consider either of those issues a big deal. Those minor things are surely not enough to consider the vehicle a lemon. I'd just drive it if it were me. Have the rotors turned if he just can't stand a little brake squeek. The gas guage isn't worth messing with imo while it's working at all. jmo

As I said, I liked the Ranger drive a bit better than the Colorado, but the Ranger they had for me to drive was a V6, I'm looking for a 4Cly. Interestingly there are many 2.3L 4Cly manual trans Rangers available. They all come with the "employee price" minus a $2,500 cash back (have to pay sales tax on this rebate), and they are giving the A/C ($850) away for free, and on the base XL model. Now we're taling some real savings. The Colorado has a similar, but less, program, and the A/C is standard. But the end result is a very competitive price with the Ranger. I am leaning toward the Colorado as I can get it with Stability Control and the Locking Differential, almost as good as 4WD without the weight and cost. I can't say I know how well it works, but in theory it looks good.The 2.8L Colorado is also more powerful, I've look it is 175hp@5+K while the Ranger is 143hp at a similar rev. And the torque: 185@2800RPM Colorade and 154@3750 for the Ranger. This says a lot more "pull out of the hole" for the Colorado. Another reason to go with the Colorado, especially if one pulls a trailer at times. Funny, I have been defending Consumer Reports in a couple of threads and now I find CR telling me the engines in the Colorado are: "a bit crude and noisy" a negative and "Cabin is fairly quiet, and the ride and handling are more accomplished than in other compact pickups." a positive. My tests left me thinking the Colorade rides like a truck too (frame) and the engine (the 5cly in this case) wasn't particularly noisy, and I have not idea what CR means by "crude". So, there is a big question in my mind on CR in this case of their testing.

High fuel consumption,, is this measured over a couple of tanks of fuel, or simply happen on just this one? The valves are hydraulic, there is no adjusting to be performed. If it was running too rich it should be setting a trouble code and a check engine light. The computer systems are pretty smart. if the convertor was plugged up, the onboard computer would actually detect that the MAF sensor is under-reporting airflow through a volumetric efficiency "VE" calculation. Now it would turn the MIL on and set a P0101 for MAF sensor performance because it would not know why the "VE" was incorrect but it would recognize this. If the emergency brake isn't releasing fully, that could seriously impact fuel useage. If you ahe been looking at this from a single tankfull, it could be the gage is doing something erratic. A fuel leak again is extremely unlikely, first you would smell it, secondly the evaporative emissions system would detect the leak and turn on the MIL (check engine light). As far as someone stealing the fuel, there is a roll-over valve, and the car also uses ORVR, On-board Refueling Vapor Recovery which between them make it virtually impossible to siphon a fuel tank. It's a real PITA when I have to service a fuel pump, not to mention a great saftey hazzard dealing with a full fuel tank that I cannot drain. The car already uses platinum plugs, in fact they should be double platinums. If there is a missfire occuring, the car would detect it and agian illuminate the MIL. It would be a good idea to get this checked, first of all it's still under the 3year- 36,000 mile warranty. One possible cause could be that the vehicle may have been fueled with E-85, and may not actually be a flex fuel truck. Although I would off-hand expect that a 3.0 Ranger would be a flex fuel, and quite capable of handling such fuel. If a problem in the feedback system occured at just the right time, the vehicle could be totally confused thinking it got refueled with E-85, when in fact it actually got regular fuel. It would take it a while to figure out that something is amiss if that was to occur. A qualifed tech, with the correct tools will make easy work of verifying the engine control system. Since this should be still under warranty, a dealer is where to go. After that if you want to go somewhere else find a shop that has invested in the Ford IDS scan tool, and is not just relying on some aftermarket 1/2 tool.