what does the coolant temp (engine temp) read with your scan tool

with car ice cold
with car at operating temp?

Also if you're getting a misfire on cyl 4 you should be getting a SES code for it. S cars are quite adept at detection of these misfires.

What kind of plugs are you using?
what kind of wires?

 

Don't go shotgunning parts at it hoping to fix it. That can cost you a lot of time and money unnecessarily. The fuel smell is either something new you didn't mention before or I just missed. Sounds like you may just have a leak in one of the fuel lines. You need to check them very closely and look for any cracks or signs of wear. Hell, I've wrapped them in paper towels before to try to find a leak. You can get a fuel pressure gauge at the zone or advance. Loan a tool things. You put a deposit on it, use it and return it for a refund. I had to get 2 at the local zone here. First one didn't work at all and upon inspecting in, it had a damaged pin that's supposed to depress the Schrader valve on the fuel line. Check yours, that may be the problem.

 

I can't find any info in the Haynes manual about the air fuel ratio, MAP sensor measurements or an air flow rating. You'll probably need access to an FSM for those numbers. Keep in mind that a leak in the MAP sensor can result in a lean fuel mixture though. I don't know if you can test that sum beech or not.

 

I'm just tossing ideas around. I won't be installing any parts until I have fully diagnosed everything. One new part in the wrong place can cause even more problems.

 

Fuel pump pressure measured at the fuel rail, is down stream from the regulator (at least I am pretty sure it is) and I am not sure what measuring anything with the ignition on (so the fuel pump will run) and the engine off is any kind of an important reading.
In general the pump is going to hit a high point well above the regulator value, and Ruby's estimated of 26 - 31#'s is a reasonable estimate to get with the engine running.
Also I am reasonably sure that unless the engine runs, the amount of time the fuel pump is going to function is a very short time interval.
So I am not sure that a reading is even available.
The regulated fuel pressure with the engine running should be adequate to determine if the pump itself is working correctly.
1. That has been my experience
and
2. A fuel pressure gauge, something I never had a need for while working on carbureted cars has proven to be very valuable when working on FI cars.

Please re-check for error codes with the Scan Tool you are using. It is if I have interpreted correctly a snap on Solus. This is a 3 or 4 thousand dollar scan tool with a huge number of options. As your car is a 97 I think it is fully in to OBD-I logic so there should be no problem in reading your car out.
With the problems you are describing there should be more than the one error code retrievable. The P0133.
I have an older version of that tool and obtained it just so I can read the error codes out on my 94 which is a pre-OBD-I logic engine management computer.
Please re-check for error codes and print them out.
I also have the MITCHELS professional mechanics diagnostics soft ware and it probably lists out the things you have measured and I'll try to look them up when I am not so sleepy but at the moment I do not see where they may affect anything relating to your loss of fuel mileage and/or hard starting.
If needed, I can also hook up the older version of the same too (the solus) to an older version of the same car which is running just fine at the moment although in need of some care and probably an oil change. Some readings can be compared at that point.

Working on today's modern electronic controlled cars requires an in depth analysis as to what can be measured as being right or wrong rather than tossing ideas out as to possible problem area's.
There are far too many things that can cause a problem up to and including multiple glitches in how things are controlled due to an ineffective sensor reading (which should flag an error). So please re-check for errors and carefully record the wording of them and as the wording can be important.
Thank you

 

just for clarity

97 is ODBII

my 91-93 haynes manual also says key on/car off (post priming) says 58-94 so rube's earlier estimate seems good. Makes sense it should not bleed off if all is well so pressure reading should "stay".

Likewise 26-31 at both idle and 3K rpm.

 

Thanks Derf,
There is a grey area in the 90's as to what is taking place.
As a back yard mechanic I have run into it a bit.