Why my WagonR CNG engine stops on its own at slow speed?

Ideally, if one plans to fit a CNG in their petrol car one should do get it done by the company or buy the car with company fitted CNG kit. Getting GNG kit fitted from outside does to many irritating problem, one of them what Amol seems to be facing. 

My WagonR outside cng fitted car a problem is car automatically stop after low speed and down gear please suggest what s problem?

Why my WagonR CNG engine stops on its own at slow speed?

Amol. Thank you for writing to us. The problem you have shared about your car automatically stopping when in low speed could be attributed to multiple things. In general, since CNG cars have a lower power output compared to the petrol version, you might not experience the same fluidity and pickup in the lower RPM as against when driving with petrol fuel. What would really help us diagnosing this problem better is information on the kind of CNG kit you are using and more details on the problem that you are facing.

The most common culprit in these cases is usually spark plugs or the plug wires. In other cases, it could also be attributed to choked injectors which might require cleaning, choked throttle body, problem with timing advancer or ECM (in case of Sequential kits). Also, a few preliminary things that you should  ensure are -

1. Engine is in good condition

2. Ignition system is in good condition

3. If your car has a distributor, then the vacuum advance mechanism works fine

4. Your sparks plugs are in good condition and are gapped correctly to 0.5-0.7 mm

Also, please feel free to detail as much as you can on the problem, like any other problems (judder, shakes, vibrations) or any other conditions you are facing the same problem in.