Chery Arizzo6 2020 random misfire

Good day everyone,

2020 Chery Arizzo6 came to my shop customer complain is car acting like crazy, some times steering wheel is heavy, gas pedal heavy, and some times car runs perfect. took a ride in it and scanned it. what I have found that is random misfire some times cylinder 2 and mostly all cylinders. codes P0300-00 & P0302-00. We have inspected plugs, coils, and injectors all working fine. erased the codes and started the car again another code showed P001678 intake cam shaft position runout. We have checked the camshaft sensors both intake and exhaust using multimeter voltage reading is fine same for the crank sensor its working fine. Sensors type hall effect pull down they are three wires (power 5v, signal 0-5v, ground). What we have found during bypass test for intake camshaft sensor & crankshaft sensor some components start to work headlights turn on & off some motors start working relays start clicking, etc. What we thought is there is short in wiring so we opened the engine wiring harness and followed the wires for both cam sensors and crank sensor and found out that there is nothing wrong with the wiring. 

We have noticed that when unplugging the crank sensor connector the misfire disappear and car does not run perfect but there is no misfire and it run way smoother. 

We are kind of lost if sensors are fine, wiring is fine, could it be the ecu? or it could be the flywheel? crank sensor mounted in the transmission housing.

We do not have oscilloscope so maybe the multimeter is not enough?

We don't want to be parts changers.

Any thoughts would be helpful. 

Thanks in advance,
Mohamed from Garage Fuji

Are you saying that when you unplug the crank shaft sensor, the scanner stops showing misfires? Because typically misfire monitoring is done using the crank shaft sensor, which would make the scanner stop reading misfires. I might look into timing at this point, you could put a vacuum gauge on the intake manifold and it should show a steady reading of vacuum pressure, if it’s bouncing all over you likely have a timing issue. You could also spray some water on ignition coils and plugs and watch for sparks shorting to the block

the car stop misfiring we hear it when we unplug the crank shaft sensor. will look into timing.

thanks for the reply

Figured it out. It was the intake cameshaft variable solenoid valve. It was dirty cleaned it and it runs perfect.