Car losing power when going up hills and trying to pick up speed. No power

Thank you it was the catalytic converter on my car.

Engine starts and is running, however engine light comes on and there is no acceleration. Unable to diagnose the problem, do you have the answer.

I have a 2004 Nissan almera 1.5 not accelerating. When diagnosed it gives me the codes p1122 and 1126. I have tested the throttle unit and the peddle on another similar car and both work fine. This problem started after I replaced the antenna ring on the ignition because it was faulty.

On Thursday my car seemed to be loosing power and then on Friday it really had no power it normally flies up hills now it does not get past 80 kms/hour on a hill. When it idles it seems like the engine wants to climb up and leave it shakes so much. Any ideas what could be wrong?

When driving up a hill my car suddenly moves very slowly, like at 15 -20 km/h and the rpm's only goes to like 2500 and then drops down quickly ( the needle in the gauge is bouncing at 2500 and back to like 1000 like every second but the car will not cut off.

The car is going a bit back and forward a lot when this happens. Car runs great on flat roads but once I start going up a hill this problem occurs. There is no loss of power or speed on flat roads.

I had a qg16 engine ( a 1.6) before in the car and the same problem occurred but the transmission felt like it was slipping and there was loss of power so I changed the engine to a qg18 ( a 1.8) and bought a new transmission.

After the engine change there is more power on flat roads and the transmission does not slip on hills. But there is the same problem of the car no being able to drive up a hill normal. If I make it at the top of a hill or halfway I have to pull over to stop for a while and when I continue to drive mostly on flat road again, the car drives normal.

There are no codes but the check engine light is on. All oils are at their levels and there are no leaks anywhere.
Please help me!

Yes, the transmission oil is good, was changed few months ago when the engine was changed along with other oils. Also plugs were changed. I heard about changing the fuel filter on the web. Do you know where it is located and will this help?

I also heard some stuff about a plugged catalytic converter, can you please give information about this? Also which part do you suggest I replace first, because I do not want to waste money since the car only gives this problem going up a hill?

Any advice and information is appreciated. Thanks

Hey Thanks for the advice Ken

So I looked for my cat converter and it was bolted on under my exhaust manifold and when I checked I found that it was changed when I had installed a new engine( it came with the engine) There isn't much of a rattling noise.

There is another box in the middle of the car I think its the resonator, could this also get plugged, there isn't a rattling noise from it.

I also removed the O2 sensor in the exhaust manifold, when I rev the engine a lot (usually at 3000 - 3500rpm) there is a backfire noise that comes through the O2 sensor hole.
Is this normal?

Also if I change my fuel filter, which I plan 2 do first, and there is still the problem, Any advice what could be the problem.
Could a bad sensor cause this, if so which one most likely. Remember the problem is only up hill and the car works great on flat.

I got my car serviced a few weeks ago and was told the back brakes were gone the brake pads were changed and the calipers had been pushing them in so the mechanic pulled them back and said they should be okay. Today car was losing power on the road and a smell of burning rubber coming from it when I pulled over. Stopped for a few mins and took off again and could feel power coming back into car - is this the brake problem again?

S reg nissan almera 1.6
i have no loss of power and fluid levels are remaining the same temperature is fine! But when I accelerate I have water coming out of the end of the exhaust smokes when cold but when shes warm this stops? Can anybody help me please?