99 Cougar No Acceleration and Shaking

ok so im not sure whats wrong here but i think its a plugged exhaust or clogged catalytic converter but whats happening is when I drive my car is lacking power huge, sometimes ill push on the gas and it will hardly move and start chugging but if i push down more it will go. When i go on on ramps to the highway as soon as i hit 70km it starts to chug then i have to push the pedal to the floor to get going,then after a while the car will start to shake after 5-10 minutes of driving and i have to let it cool down or it will keep shaking or just go back onto city roads and it doesnt shake as bad. Once im off the highway my car will begin to shake more at 20km and 60km i have no clue why, any help would be huge thanks

No one will know where to start since you didn’t give any info about the car. How many miles are on it? How old are the spark plugs and wires? Air filter? Fuel filter? What else can you say about basic maintenance? Any check engine light?

Engine-wise the car needs 4 basic things to go: fuel, air (both intake and exhaust); compression, ignition.

So far all anyone could say is that you have a problem with one or more of these four things.

So if any of the basics - spark plugs & wires, distributor cap/rotor (of so equipped), air & fuel filters - have been neglected, then get them up to date and see where things stand.

If you know anyone with a vacuum gauge who knows how to use it you can quickly and easily check for vacuum leaks (not likely) or exhaust blockage (certainly a possibility). A quickie, shadetree way to find out about exhaust blockage is to pull the upstream O2 sensor and see if it makes a difference. You can’t drive around that way, but if the power issues go away you can be pretty sure about the exhaust blockage.

You need to put a fuel pressure gauge on it.

When the plugs are removed for inspection/removal, a compression test would be in order.

You mentioned letting the car cool down. Is it overheating? Are you losing any coolant?

my car is a 1999 cougar v6 with 220,000km, the spark plugs are about 6 months old and the wires are about 1 month old, my air filter got changed 1 month ago and my fuel filter about 2 weeks ago! yest i do have a check engine light but that only brings up the p1744 code with is a transmission slip which i have always had ever since i bought the car, and that only happens after long periods of driving and once i shut it off its fixed so thats a whole different problem on its own. I am not losing any coolant and my car has been overheating after long periods of use of about 20 min, the needle will move to about 3/4 then when it breathes it will go right back to half

You should get it checked out for a head gasket problem - that will kill the compression and eventually wreck the engine. Checking for exhaust blockage is also in order. You can try the O2 sensor removal as a quick diagnostic aid.

To be frank… no offense … you’ve already fried it under those conditions or another owner had… with that mileage. Burned valves probably the bearings are gone anyway, cam etc. rebuild or get an exchange if the car is in decent shape…then transmission?

good luck.

Don’t miss the fact that he’s using KM, not miles…220,000 is only 136K miles, so it’s not that bad. Having said that, it’s also 12 years old (more likely 13).

Remove an oxygen sensor between the catalytic converter and manifold or disconnect the front pipe, whichever is easier, and try driving it. It will be loud but will tell you if the problem is exhaust blockage. If you suddenly have a lot more power , the problem is exhaust blockage.