HI there,
For couple of weeks, my car became slow running on hills upon giving gas it responds slow, it looks like car is trying hard but not can be seen on power.
Its HOnda Civic Lx 2005.
I dont know what would be the problem? I can guess only, it may be spark plug, misfiring coil or fuel filter.
Does anyone has any idea?

 

have never seen an actual plugged fuel filter causing driveability issues. but in theory, sure it can - I just have never seen it in a million miles driven across many cars.

i have seen things like plugged exhaust, plugged catalytic converter, bad ignition coils and plugs, and badly plugged air filters cause those types of issues. is the car automatic or manual?

 

Same issue except it throws a p0301 Cyl 1 misfire. If your engine light is flashing that means it's misfiring for more than 5 seconds.

Plugged fuel filter will cause stalling to the point that it stops running. I believe it will throw a code before it gets that bad but not always.

You can buy an ODB2 meter for fairly cheap online at like Amazon ( ) is cheap and works. Not sure about the Bluetooth ones but probably be good for constant monitoring.

If the engine light isn't on than you need to do a bit more poking around. Bbarbulo has a few of the common causes but I'd expect it to through a ODB2 code/engine light on which would help to get it scanned.

I've had 2 civics that both threw a bad O2 sensor but only one of them began misfiring but haven't fixed it yet. No issues idling for over 50k km with bad O2 sensor but reduced gas mileage no doubt.

 

I have many times seen a fuel filter, or old fuel pump cause this. Or a child forgets to put the pump sock on and pumps the injectors full of dirt.

dirty fuel filters Are not my first suspect but its happened to me many times. Mabye its just the area i live in

 

I have the same issue on my 2003 honda civic 1.7l kinda. It struggles like hell to accelerate to 40 but after that its pretty smooth and speedy. She'll barely go past 85-90 now tho. I could be going 60 up a hill holding the gas and itll slow to 40 or 35 and take a minute to get back up to speed, and if i need to accelerate up the hill i have to step on it and force it to make that gear change(which i hate having to do to the poor car) It used to overheat all the time last summer but just stopped so idek. just want my accelerating power back