I recently bought a 40th anniversary edition GT convertible from a single owner...couldn't pass up the price. I know he had issues with the check engine light fuel evap system . replacing the reservoir assembly and light went out. Then it came on again and replaced fuel feed SOBS and light went out. Came on again replaced fuel cap and light went out. When I received the car the check engine light and check fuel cap light came on. Went to dealer and he found an evap line to gas tank disconnected. Reconnected and lights went out. BTW they found tie rods shot and I had them replace them. All was good for about 100 miles and check fuel cap light came on. I took it back to the dealer and they said the fuel pressure sensor was bad and it's been discontinued. They can get a replacement but they are trying to find the fuel pressure sensor assembly...are they blowing smoke and trying to hook me for another thousand bucks. (I can find the Motorcraft sensor but not an assembly?? Any advice would be appreciated
For the record, EVAP problems can be some of the most difficult to fix. This goes DOUBLE if the person doing the work is trying to fix it by "parts swapping" to a solution. The dealer doesn't have an incentive to spend time reviewing ODB2 scan tool data to UNDERSTAND what's wrong. They will make more $$ by selling YOU parts.
Here's some information on an affordable ODB2 scanner. IF you learn how to use this powerful tool to analyze what the PCM has to say, there's a high likelyhood that it be possible to have figured out that the fuel tank pressure sensor (FTP) was not reading correctly without ever turning a wrench. For that matter, even getting your hands dirty.
While working on your car have you ever wanted: to find an ODB2 operational PID value (say fuel pressure or MAF)? How about graph a PID value over time? Or compare multiple PID's over time? Access a bi-directional PCM control such as test a...
IMO the person doing the work has not done you any favors. They did not TEST the ability of the EVAP system to hold pressure before firing the parts cannon at you. They did not look at the FTP to see if it was sending a "reasonable" value before dropping the tank.
Check out car-part.com for an alternate source for used parts. You may have to buy an entire gas tank just to get the FTP sensor.