97 grand marquis,4.6 engine. idles good, but when you go anywhere over 1/2 throttle to WOT it just bogs like a plugged converter. Took exhaust down from engine and still have the same thing.Vacuum gauge at PVC shows 20lbs at idle, but when i go over 1300 rpms it goes to zero and bogs down.fuel pressure at rail is 42psi,and when WOT it maintains 42psi. Checked EGR valve for sticking,checked tps and it is good.checked air filter and mass air flow sensor for any restrictions But none found. What am i missing here????

sounds like low fuel pressure enough for idling but to little during accelererarion. eg. failing fuel pump,blocked fuel filter or fuel pressure valve or sensor

Evinrude 50 HP Bogs at WOT - MarineEngine

www.marineengine.com > ... > Johnson Evinrude Outboard Archive

Aug 6, 2002 - 17 posts - ‎3 authors
83 50 HP Evinrude - sat out in weather for 4 yrs. Been cleaning ... At WOT, she bogsdown. Up to. ... Yes, this boat/motor is new to me. Actually ... Mercury 50 1987 bogs down when full @ full throttle
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motor bogs down at full throttle Page: 1 - iboats Boating Forums ..

if you follow the fuel rail gas line, it goes to the filter.
for sure.
4.0L 97 , we have the FSM to see all that , ive posted it 100s of times here. that link.
please explain the bog more clearly.
cold or hot engine or both.?
is it just tip-in throttle bogging , only then POWER catches, up?
while bogging can you go to WOT and see if it has full power now?
ever get a full 60k mile tune up with new spark parts. and filters.
is engine misfiring.
is engine idle too low rpm or too high with a hot engine?
is fuel old.
did car sit for long time ? unused?

"not getting gas" can be 2 things, bogging or misfiring
they are night and day different, one is like pulling a dead weight
the misfire is violent engine shaking,
see?
and 2 different diagnostic paths due to that ...

if wot is ok, then that implies fuel pressure is good. and filter.
see?

WOT = WIDE OPEN THROTTLE.
i drove a 99 XJ for 300k miles. and know it well..

free fsm
click fuel system here 96-2001 xj
http://www.jeep4x4center.com/knowledge-base/index.htm?utm_source=cj#service

see that page? page 14 in PDF
if you changed the pump, you had it in your hand.
unknowing
its on top of the fuel tank pump RACK.

if engine is tuned up,?
and power is low at wot,
i check fuel pressure live.(under varying engine loads)
if the pressure is out of spec, i get a new filter and PPR.
if pressures are in spec. dynamically.
i find out why the PCM is under-injecting.
ask how. its not hard.
(bad MAP?, , injector balance tests?)

It is probable a clogged catalytic converter if it has one. Sounds like it is pluged or a valve is not opening when throteled.

Check idle speed, air flow speed, oxygen sensors . Check fuel manifold pressure. If the engine runs ok but will not rev up check the cat converter by hitting with the heel of your hand and listening for rattles as they are prone to failing and blocking up the exhaust system which stops the motor from accelerating

I think its time to check exhaust back pressure. You can install a gage where the o2 sensor screws into the exhaust BEFORE the catalytic converter.

Have you checked the fuel pressure while pressing the gas pedal? Pressure should stay above 40PSI

I've owned one of these. you can try to clean the MAF with brake cleaner. but if that doesn't work you'll have to replace it. the car can't tell how muich air is entering the engine to properly meter the fuel. so what you get is a lean misfire. fix it soon. running the engine lean means it's running hot internal temperatures which can damage expensive things ie. catylitic converters.

Sounds like the catalytic converter plugged. Don't continue to drive car till something gets done with this as you can damage the engine by the excessive heat. Do something but remember it is illegal to take these converters off and not replace them, so be careful what you decide to do. good luck with it.

Recall Summary 00-03 LS ModelsON CERTAIN PASSENGER VEHICLES EQUIPPED WITH 2.2L L4 (L61) ENGINES, A FAILURE OF THE IGNITION CONTROL MODULE MAY CAUSE DETERIORATION IN IDLE QUALITY, REDUCTION IN OVERALL ENGINE POWER, AND THE VEHICLE MAY BE HARD TO START. CONTINUED OPERATION OF THE VEHICLE AFTER SUCH AN IGNITION MODULE FAILURE WILL RESULT IN THE ¿SERVICE ENGINE SOON¿ LIGHT FLASHING, AND MAY LEAD TO SECONDARY FAILURES OF THE CATALYTIC CONVERTER, OXYGEN SENSOR, AND EXHAUST RESONATOR. OWNERS SHOULD CONTACT SATURN AT 1-800-553-6000, PROMPT 3.