Logic says the gas treatment is the likely cause. Could have fried O2 sensors/catalytic converter and has thrown the fuel/air ratio out of whack (rich).

Are you getting any codes?

 

I tend to agree w/ the above.

What specifically was the gas treatment you used?

 

Dude,
You are totally funny.
You have a funny sense of humor.

You are trying to replicate the heat of the sun under your land rover.

Eventually, the catalytic converters could catch your underside on fire -
the rugs will start to burn and you'll have a fire ball.

You need to read codes.
Figure out why you are over fueling.
You may have ruined your cat converters all ready.

Quit being funny and take this seriously.

Your MAF is not telling the ECU to fuel properly.
You probably got codes pending out the wazoo.

What MAF did you put in your truck??
Where did you get it?

-----
I had a Jaguar XJS where as it
had one cat glowing red.
The car was about to catch on fire.

By luck, I was in the driveway and the hose was handy.
Lots of hissing and steam and we were saved.

Turns out --
On an XJS there are two complete fueling systems and ignition systems.
The ignition system on 1/2 of the engine can fail.
And, the fuel system keeps fueling.

The cat goes super nova.

This will be in your future. Unless you fix that MAF

 

What fuel treatment did you use?

 

I blame a bad cat.

 

Thank you guys for all of your supports. First, I used GUMOUNT regane complete fuel cleaning system. I bought the m.a.f from advance auto parts and it is a re-manufactured one. This morning, I tried putting back my old mass airflow sensor and the car worked better than when i had the new one on. The only problem is the car shakes once in a while. when the engine is working it shakes just a little bit. i can hear a groaning noise coming from the exhaust and a lot of black smoke is coming out of the exhaust pipe.

 

First, Gum Out is Junk, second, it didn't cause your problem, 3rd. quit driving it unless you want a huge repair bill.
Is your service engine light on if so what are the fault code numbers, what color is the smoke, white, black or blue?
Don't take this wrong but you don't sound at all mechanical so that being said, do you have a Rover mechanic, that is any good other then the dealer, if so have it towed to him for help.

 

if your check engine light is on then you should not be driving it.

If you keep driving it - looks like it will catch on fire.
The black smoke is unburned gas.

The job of a Cat converter is to BURN UP unburned gas.
The converter does this by heat.
It is a little furnace under your Rover.
There is always a little unburned gas and other pollution type of
stuff.

If you keep driving it and the engine keeps dumping raw gas into the cat converter
and it catches on fire.

Then - soon - you will not have to worry about it after a while.
It will turn into one melted blob.
A burned out shell - like cars in Iraq or Syria.

If it catches on fire, put that on youtube.

You'll get 1,000,000 hits on your video.
Everyone loves watching someone else's car burn up.

Sad statement about humanity.

 

I dont think its a sad statement so much as its just one of those things ya dont see every day.

 

Get a digital temperature gauge for your vehicle. Lightly rev the vehicle while parked, watch the temperature raise very quickly.