The engine won’t stay off to pass inspection despite repeated attempts by my mechanic to find the problem
So are you just voicing a complaint, or would you like to ask a question?
What are the codes that are triggering the light? What has the mechanic done? It is impossible for anyone to say anything at all w/out that info.
The codes will be in the forms of a letter followed by 4 numbers such as P0123.
Ask your mechanic for the codes - actual code, not any interpretation - and post them. If you can’t get it from them go to a big-chain auto parts store such as Autozone where they will often read them for free.
Get the codes and post them - include what your mechanic has done. Include the maintenance history especially with regards to how that matches what the owner’s manual calls for. (E.g. “regular oil changes” is not enough info and is probably irrelevant to this).
My mechanic has done the following changes: a fuel filter change; a fuel injector flush; repaired the intake manifold runner control activator; changed the plenom gasket, changed the throttle body gasket.
ok - but what are the codes?
I got the codes. They are:
PO171 and PO174
Check out this discussion: http://www.aa1car.com/library/ford_lean_codes.htm
There are lots & lots of possibilities, and all of them have to be chased down. I always start with the simplest - vacuum leaks. I’d imagine that the intake & tb gaskets were replaced with this in mind, but was there ever any verification that either was leaking? Has the fuel pressure been checked? The MAF sensor cleaned? Etc.