In the rain only the car does not start
 

2001 Cnevy Express 3500 5.7L CNG/Gas. When the rain only!!! the van does not start. An arrow of fuel will goes for very high regardless how much gas in the tank. It crank but not start. In the warm weather everything is normal. And there is a way to start!!!! After to disconnect MAF sensor the engine will start and work normally.

sounds like an distributor problem. if this engine is still running one...inspect the cap/rotor and ignition coil.

thanks, do you believe or not but the coil and distributor I did already replaced.

buy a spark tester....when the fault occurs test for spark at the spark plug wire. then you can rule it out and focus elsewhere.

I am always taking out a one high voltage wire, plug another spare spark, touch the ground... crank...

takes way more spark demand to ignite a lean fuel mixture in a cylinder than to produce a spark next to grd screw driver or block the way yr doing it.
when you see a spark from a test with a spark tester; you know it can fire a mixture....grd plug way...it a guess.

Sorry, o disagree... Under compression it needs even less spark to work well.

just bc a spark plug jumps spark next to grd screw driver or block does not mean it will fire a lean mixture in the cylinder. That is the purpose of spark tester; creates a spark demand

Sir,what you are saying it looks absolutely nonsense for me... Please do not make any more comments. Do not waste your time and mine. Actually on some other web site I found a smart guy.
Want to be rude. Take a break

I wonder if he knows what he sounds like.