My father in law's truck (98 Chevy Silverado 1500) is having problems starting up.

When you try to crank it there's this fluttering sound. I know that usually this sound is caused by a loose battery terminal but it's brand new battery and the terminals have just been cleaned and tightened down. The other odd thing is that once the fluttering starts the needle on the speedometer just goes nuts. It flutters up and down between 0 and 15/20 mph. Weird. We were thinking that there may be a distributor or coil issue but I don't even know where to look.

Any help guys? I'm trying to suck up to the in-law.

 

This primarily depends on the nature of the problem: if it can be identified as an electrical problem, you should check the connection from the battery to the starter. Use a portable voltmeter to see how much power the starter is getting on ignition. I’m willing to bet the terminal to the starter is not getting enough power. . . otherwise the engine would turn over. If the starter is getting power, it might be a bad starter.

Good luck