I believe I have found the FPR on my 4.9L (93 Sedan Deville) Since it is not a N* it does not have a beauty cover, but it looks similar to the one pictured and is just to the driver side of the throttle body sort of under the air intake housing.
I havent checked it recently, last time I checked a few months back I did not see a leak with engine on or off, so I figured it is good. Lately though the car has become hard to start when warm, After driving around and stopping for a few minutes then restarting I have to hold the key all the way over for several seconds for it to start up, Yet it always starts first try when cold, like first thing in the morning or when I leave work/school after a few hours.
I have just had the starter replaced twice in the last year or so, before I had it done the first time it got hard to start no matter hot/cold. After replacing it all was well for a month, then with no warning I was stuck at a gas station unabable to get it started. After checking and replacing the battery I had it towed back in and they replaced the entire starter and it was fine up until recently when I have hot start troubles every time.
My question is how do I troubleshoot this to determine if this is a sign of my starter going out again, or an FPR issue. I havent seen any leaks at all every time I checked it, Any other way to test starter or the fpr without just replacing it?
EDIT for a.johnson1
Have you checked for any problems with the starter? If its constantly getting worse no matter cold or hot it sounds like what I just described. You mention your problem started with cold starts, I wasnt sure if your hot starts have started to be more difficult or not. Maybe describing the sound it makes may help lol
When I had my starter trouble it was sort of a whining sound, never sounded like it tried to turn over.