I Have a 1999 Grand Marquis that's misfiring losing power high fuels smell come from tail pipe. While driving for a min check engine light blink on in off put it on a machine in it told me

you have a leaking fuel pressure regulator-Denny

Does the smell happen if you are running the hvac on just vent ?
The ac itself would not cause a smell unless the clutch on the compressor were slipping and you would probably hear that.
Its a sealed system just like your fridge at home.
So it could be something in the engine compartment that is coming thru the vent when the ac is on. The most common smell is a musty or mold smell from moisture inside the hvac.

I answered this already

If a MIL Lamp is flashing please do not use the car

That on a ford that is called a Class A Cylinder misfire & will
destroy your exhaust converter, as well as possible other
engine damage,work on the misfire issues

Can not nor should you jump a dead battery

You need a good battery or fully charge yours
& then check fuel pressure with a gauge at fuel
rail port

Trouble Code: P0420

Catalyst System Efficiency Bank 1 Below Threshold

Possible Causes:


Air leaks at the exhaust manifold or in the exhaust pipes.Catalytic converter is damaged, contaminated or it has failed.ECT/CHT sensor has lost its calibration (the signal is incorrect)Engine cylinders misfiring, or the ignition timing is over Engine oil is contaminatedFront HO2S or rear HO2S is contaminated with fuel or moisture.Front HO2S and/or the rear HO2S is loose in the mounting hole.Front HO2S much older than the rear HO2S (HO2S-11 is lazy).Fuel system pressure is too high (check the pressure regulator).Rear HO2S wires improperly connected or the HO2S has failed.Here is the causes for the code.It\'s a process of elimination,till problem goes away.Could be Oxygen sensor,but maybe not.

If the check engine light is not on, I doubt there is much you can do.
It sounds like one of the engine temp sensors or one of the other sensors. The engine temp sensor and the intake air temp sensor tell the computer what the outside air temp is and the coolant temp which allows the computer to regulate the amount of fuel going thru the injectors. Generally if one of the sensors has failed the check engine light should be on.
It could be low fuel pressure too.
You may have to have a shop check the sensors with a scanner and the fuel pressure with a gauge.

Hello
The engine and transmission in this cars drive train are fully electronically controlled by a computer called the PCM (Power Train Control Module). Whenever a problem like this occurs the computer stores a record of the problem (there are of course some exceptions to this, like the fuel pump for instance) in the form of a fault code in its memory, to read these fault codes you must have the systems memory scanned with a special tool. Once the fault code(s) are read you then must perform the appropriate diagnostic testing to find and resolve the problem(s) DO NOT REPLACE ANY PARTS UNTIL THE DIAGNOSIS & TESTING IS COMPLETED.

You work on Check Light issues first,so check
for codes & proceed from there.

Need some knowledge or a trouble chart,as codes
don't tell you what is wrong or what to replace

I am having a oil leakage problem and it seems its from the gear hole at the bottom. Secondly my car vibrates too much when driving at a speed of 140kph or above, Pls advice me a best help solution for both the cases.

I would check the exhaust pipe a little closewr. White smoke can also mean a blown head gasket. Check the tail pipe to see if moisture is present. Also check coolant level. A blown head gasket can also cause related problems.

Bill