Serious Issue?

[Harley Edition Titan]

I went to start my truck today after not starting it in about 4 days because I've been riding my motorcycle everywhere. I started it and it took a little while to roll over and start up but when itfinally started, it was running REALLY rough and I knew something was wrong because not only did it sound bad but the RPM and the speedometer where shaking at 0 (BOTH AT 0 and moving about an 1/8 inch up and down) and my battery gauge was acting like my truck wasn;t started and my oil pressure was at 0. I as fast as I noticed the oil pressure wasn;t there turned the truck off and checked under it for oil and there was nothing coming out so I checked the oil level and it was fine. So I started it again and it did it again only this time my engine game off this funky smell so I revved a lil bit and the RPM still was shakin around the 0 mark. I shut the truck off again then tried a third time in hopes it would start normally and it did. It's been running great since that this morning, I've driven 50 miles and started and shut it down 4 or 5 other times today. If anyone has any info as to what this might be let me know. BTW the service engine light NEVER same on. WIERD STUFF. PM me and let me know thanks guys.