Check engine light came on at 160,000 miles,

Oil being a quart low is not the problem. 160,000 miles is the problem. Give it up!

First Zach , you need to know how all this thing's work ! The gauges get info over serial data bus from SJB - smart junction box which gets the info from the PCM - engine computer . All this is designed to cut down on wiring , Coolant temp . fuel gauge sending unit , vehicle speed sensor , tach etc. are all inputs to the PCM .The PCM sends this info on the C.A.N. data bus where the instrument cluster microprocessor reads the data and moves the gauges ! The light's also are controlled by the SJB -body computer . The light's are PWM pulse width modulated - How to Diagnose Controller Area Network CAN The first place is to start by hooking up a diagnostic scan tool an check for DTC'S diagnostic trouble codes . The last Ford i had in my bay was a 2006 explorer . had this type problem , had U codes communication problems . Vehicle needed a new SJB $899 buck's an then it had to be programmed , another $300 .This is something you need to take to a qualified repair shop . Who know how it works and what to check and how to check it .
It could be as simple as a lose ground wire . But are you prepaired to take the instrument panel out to get to it .

need more info does it run warm

MIL light comes on for many many reasons, you need to scann the ECU for codes. Any parts place can help you scann for free.

The information below was complied by me, it explains what causes the check engine light to come on and the process of finding the cause.

When the Check Engine light (or Service Engine Soon) is turned on, the systems computer control unit (called the PCM) has sensed a fault in the electronic controls of the engine and/or the emission system. When this happens you will seldom feel the car engine run any different. There are about 200 possible system faults (the gas cap is just one of them) that turn the Check Engine light on, to know what has developed a problem you must have the system tested, this is called an OBD2 fault code test, Kragen/Oriley and Autozone parts stores (USA only) do this testing for free.

MY 1992 MPV 4wd "check engine" light came on when I hit 160,000 miles, as I was told it might...I was also informed I had to take it to a mechanic to have it turned off...there's nothing wrong, so I just deal with the light.

NORMAL MAINTENANCE @ 100,000 MILES (160,000 Kilometers) - EXHAUST SYSTEM - INSPECT

NORMAL MAINTENANCE @ 100,000 MILES (160,000 Kilometers) - FUEL SYSTEM - INSPECT

NORMAL MAINTENANCE @ 100,000 MILES (160,000 Kilometers) - AIR CLEANER/ELEMENT - REPLACE

NORMAL MAINTENANCE @ 100,000 MILES (160,000 Kilometers) - FUEL FILTER - REPLACE

NORMAL MAINTENANCE @ 100,000 MILES (160,000 Kilometers) - SPARK PLUGS - REPLACE

NORMAL MAINTENANCE @ 100,000 MILES (160,000 Kilometers) - TIRES - ROTATE - [Tires should be rotated every 5000 to 8000 miles, and/or at maintenance I or II service intervals.Check tire pressure, thread depth and wear.]

second hand engine ,bewst advice here is to trade car in under the goverment scrappage scheme

Go to auto parts store and have it checked for free. They will give you codes and meaning. It is often something minor like a new gas cap.

There should be a reset switch that turns the light off. Some vehicles require a code scanner tool to reset the check engine light. On some Isuzu models you have to remove the instrument cluster and move a screw from one hole marked KSW to another hole with the same KSW marking (it may have tape over the second screw hole). Other Isuzu models may have a small switch on teh back of the instrument cluster or may have a different marking on the screw holes (some were marked wit the letter B on both holes). The O2 light usually comes on at 90,000 mile increments which is when Isuzu recommends changing it.