I've recently bought a 2010 chevy cruze LS and I experience the following issue: when i accelerate and the engine goes above 2000 rpm it is starting to make a humming sound (it sounds like some sort of air leak to me, like that sound you hear when the exhaust system has a leak) and lacks power, sometimes it pulls well but most of the times it struggles to accelerate, other symptom linked to this issue is the bad fuel economy (it began to take 17 liters per 100 kilometers - 13.8 US mpg), it's a heavy car but still; another symptom: lately when I start it cold i have to let it about 30 seconds to one minute to warm up, as in this period, the engine idles rough and if I try to rev it up the exhaust fumes will smell like gasoline (i think this could be a sign of a too rich mixture ?)
As I've read through the forums, some people say this might be the throttle body sensor, mass airflow sensor or the accelerator pedal but I am not quite sure what part I should change in order to solve this.
There is no check engine light on (or other light in the dash which could indicate an issue)
The previous owner didn't changed anything on it other than oil and filters
Below, i let the car specs and what I did so far:
Engine: 1.6L petrol 113HP (euro V EU spec)
Transmission: 5 speed manual
Mileage: 84 000 km (52 000 miles)
Trim level: LS
Country: EU (state: romania)
Troubleshooting steps and maintenance I've did so far
- changed the timing belt and water pump
- brand new ignition coil
- changed oil & oil filter
- changed air filter
- cleaned throttle body
- checked the car for errors and there are no errors/warnings active
I've noticed at idle it indicates a 33% (45% with AC on) load on the engine but I cannot say if this is right or wrong.
I've attached a few screenshots from the OBD II testing software.
If you can help me with an advice on which part should I change to solve this, I'll be very thankful.
I've just noticed while driving the car that if i hold the accelerator pedal within a extremely short range (pressed only a little bit) the car accelerates well and the noise is gone.
I've been to a local freelance repair technician for a proper diagnosis - all the sensors, throttle body and accelerator pedal are within parameters, no issues
I've noticed the flow of exhaust out of the tail pipe is too little, compared to my previous vehicle (which now belongs to my father), after driving for a while it is pretty hot and also smells like some heated up moist air or rotten eggs, i thing the catalytic converter is clogged, I think before replacing it I'll go to a shop which claims they clean up catalytic converters with some fancy apparatus and some special cleaning agent, I'm just curious to see if that's legit or it's just snake oil, for 50 euros it's worth a try.