Astra 2.0 starter problem

Hello people, I'm new here. So they know how to apologize any incorrect.
I tell you that I have an Astra Naftero with CNG Mod 99 Motor 2.0 and I have a couple of problems that I do not know if they will have a relationship.
On the one hand it is difficult for the car. I have to give him several times and I am afraid to break the start like this.
And on the other hand when I walk a lot and I demand it an indicator on the dashboard q does not mean. It is a quandradito that inside has a symbol as a fan. Oh and I tell you that I change spark plugs and cables, distribution belt and tensioner, also the thermostat. In addition the mechanic that did the work put the scanner ym said that it does not mark any fault. For the height when he was there the car started well. I hope you can help me. Thank you so much.

First of all you say that the vehicle has CNC. I calculate that the start is done to gasoline. The issue is that once the injection is to CNG, it is no longer necessary to do with which the second problem should not have a relationship at least directly. I would tell you that the starting problem in CNG cars often goes through the little use of the fuel pump. On the one hand, the fuel is made to be lost in non -dema time and on the other the pump perhaps works but does not possess the correct pressure, this may be due to the bad fuel conditions that could influence the pump, or soble to the pressure regulating valve, or on the combutible filters not only the external replaceable but the filter piece that is found in the pump which is located inside the fuel tank. I would recommend: Remove pump Make tank place Place new fuel Clean Bulk through it Clean circuit and regulatory valve. In addition to cleaning injectors with ultra sounds. so that the whole circuit is perfect. From there you will not have problems that if every two months you must almost use the fuel and then recharge and do not get lost. The indicator does not know what it is. It can be perhaps one that is a Maripoza valve is like two parallel lines and among them a diagonal or a more concrete fan with a more concrete way, I would tell you that this must be rather related to some adaptation of the CNG team. Which depending on the equipment and the installer may be totally correct, this is not due to the fact that when using ECU ECU COMPUTER of the car makes reads which do not give wrong the GNC equipment emulates that everything is OK. And this can generate some flla that is entrusted to the board. But while they have gnc. What indicates of computer data are related to the CNG team and since the only ECU that is used is the signal to generate the spark plugs. The rest does not meet function. Greetings and luck

For me it is the precion of NAFTA at the time that you leave it for a while the gasoline is downloaded to the tank and you stay without precion in the same pump has a retention valve that may not work well